1. 06 Feb, 2015 1 commit
    • Lv Zheng's avatar
      ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag · ad479e7f
      Lv Zheng authored
      By using the 2 flags, we can indicate an inter-mediate state where the
      current transactions should be completed while the new transactions should
      be dropped.
      
      The comparison of the old flag and the new flags:
        Old			New
        about to set BLOCKED	STOPPED set / STARTED set
        BLOCKED set		STOPPED clear / STARTED clear
        BLOCKED clear		STOPPED clear / STARTED set
      A new period can be indicated by the 2 flags. The new period is between the
      point where we are about to set BLOCKED and the point when the BLOCKED is
      set. The new flags facilitate us with acpi_ec_started() check to allow the
      EC transaction to be submitted during the new period. This period thus can
      be used as a grace period for the EC transaction flushing.
      
      The only functional change after applying this patch is:
      1. The GPE enabling/disabling is protected by the EC specific lock. We can
         do this because of recent ACPICA GPE API enhancement. This is reasonable
         as the GPE disabling/enabling state should only be determined by the EC
         driver's state machine which is protected by the EC spinlock.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Tested-by: default avatarOrtwin Glück <odi@odi.ch>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      ad479e7f
  2. 05 Feb, 2015 17 commits
    • Lv Zheng's avatar
      ACPI / EC: Update revision due to raw handler mode. · a8d4fc22
      Lv Zheng authored
      The bug fixes around GPE races have been done to the EC driver by the
      previous commits. This patch increases the revision to 3 to indicate the
      behavior differences between the old and the new drivers. The
      copyright/authorship notices are also updated.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      a8d4fc22
    • Lv Zheng's avatar
      ACPI / EC: Reduce ec_poll() by referencing the last register access timestamp. · 9e295ac1
      Lv Zheng authored
      Timeout in the ec_poll() doesn't refer to the last register access time. It
      thus can win the competition against the acpi_ec_gpe_handler() if a
      transaction takes longer than 1ms but individual register accesses are less
      than 1ms.  In some cases, it can make the following silicon bug easier to
      be triggered:
       GPE EN is not wired to the GPE trigger line, so when GPE STS is already
       set when 1 is written to GPE EN, no GPE can be triggered.
      
      This patch adds register access timestamp reference support for ec_poll()
      to reduce the number of ec_poll() invocations.
      Reported-by: default avatarVenkat Raghavulu <venkat.raghavulu@intel.com>
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      9e295ac1
    • Lv Zheng's avatar
      ACPI / EC: Fix several GPE handling issues by deploying ACPI_GPE_DISPATCH_RAW_HANDLER mode. · ca37bfdf
      Lv Zheng authored
      This patch switches EC driver into ACPI_GPE_DISPATCH_RAW_HANDLER mode where
      the GPE lock is not held for acpi_ec_gpe_handler() and the ACPICA internal
      GPE enabling/disabling/clearing operations are bypassed so that further
      improvements are possible with the GPE APIs.
      
      There are 2 strong reasons for deploying raw GPE handler mode in the EC
      driver:
      1. Some hardware logics can control their interrupts via their own
         registers, so their interrupts can be disabled/enabled/acknowledged
         without using the super IRQ controller provided functions. While there
         is no mean (EC commands) for the EC driver to achieve this.
      2. During suspending, the EC driver is still working for a while to
         complete the platform firmware provided functionailities using ec_poll()
         after all GPEs are disabled (see acpi_ec_block_transactions()), which
         means the EC driver will drive the EC GPE out of the GPE core's control.
      
      Without deploying the raw GPE handler mode, we can see many races between
      the EC driver and the GPE core due to the above restrictions:
      1. There is a race condition due to ACPICA internal GPE
         disabling/clearing/enabling logics in acpi_ev_gpe_dispatch():
           Orignally EC GPE is disabled (EN=0), cleared (STS=0) before invoking a
           GPE handler and re-enabled (EN=1) after invoking a GPE handler in
           acpi_ev_gpe_dispatch(). When re-enabling appears, GPE may be flagged
           (STS=1).
             =================================================================
             (event pending A)
             =================================================================
             acpi_ev_gpe_dispatch()    ec_poll()
               EN=0
               STS=0
               acpi_ec_gpe_handler()
             *****************************************************************
             (event handling A)
                 Lock(EC)
                 advance_transaction()
                   EC_SC read
             =================================================================
             (event pending B)
             =================================================================
                   EC_SC handled
                 Unlock(EC)
             *****************************************************************
             *****************************************************************
             (event handling B)
                                         Lock(EC)
                                         advance_transaction()
                                           EC_SC read
             =================================================================
             (event pending C)
             =================================================================
                                           EC_SC handled
                                         Unlock(EC)
             *****************************************************************
                 EN=1
         This race condition is the root cause of different issues on different
         silicon variations.
         A. Silicon variation A:
            On some platforms, GPE will be triggered due to "writing 1 to EN when
            STS=1". This is because both EN and STS lines are wired to the GPE
            trigger line.
            1. Issue 1:
               We can see no-op acpi_ec_gpe_handler() invoked on such platforms.
               This is because:
               a. event pending B: An event can arrive after ACPICA's GPE
                  clearing performed in acpi_ev_gpe_dispatch(), this event may
                  fail to be detected by EC_SC read that is performed before its
                  arrival;
               b. event handling B: The event can be handled in ec_poll() because
                  EC lock is released after acpi_ec_gpe_handler() invocation;
               c. There is no code in ec_poll() to clear STS but the GPE can
                  still be triggered by the EN=1 write performed in
                  acpi_ev_finish_gpe(), this leads to a no-op EC GPE handler
                  invocation;
               d. As no-op GPE handler invocations are counted by the EC driver
                  to trigger the command storming conditions, the wrong no-op
                  GPE handler invocations thus can easily trigger wrong command
                  storming conditions.
               Note 1:
               If we removed GPE disabling/enabling code from
               acpi_ev_gpe_dispatch(), we could still see no-op GPE handlers
               triggered by the event arriving after the GPE clearing and before
               the GPE handling on both silicon variation A and B. This can only
               occur if the CPU is very slow (timing slice between STS=0 write
               and EC_SC read should be short enough before hardware sets another
               GPE indication). Thus this is very rare and is not what we need to
               fix.
         B. Silicon variation B:
            On other platforms, GPE may not be triggered due to "writing 1 to EN
            when STS=1". This is because only STS line is wired to the GPE
            trigger line.
            2. Issue 2:
               We can see GPE loss on such platforms. This is because:
               a. event pending B vs. event handling A: An event can arrive after
                  ACPICA's GPE handling performed in acpi_ev_gpe_dispatch(), or
                  event pending C vs. event handling B: An event can arrive after
                  Linux's GPE handling performed in ec_poll(),
                  these events may fail to be detected by EC_SC read that is
                  performed before their arrival;
               b. The GPE cannot be triggered by EN=1 write performed in
                  acpi_ev_finish_gpe();
               c. If no polling mechanism is implemented in the driver for the
                  pending event (for example, SCI_EVT), this event is lost due to
                  no GPE being triggered.
               Note 2:
               On most platforms, there might be another rule that GPE may not be
               triggered due to "writing 1 to STS when STS=1 and EN=1".
               Then on silicon variation B, an even worse case is if the issue 2
               event loss happens, further events may never trigger GPE again on
               such platforms due to being blocked by the current STS=1. Unless
               someone clears STS, all events have to be polled.
      2. There is a race condition due to lacking in GPE status checking in EC
         driver:
           Originally, GPE status is checked in ACPICA core but not checked in
           the GPE handler. Thus since the status checking and handling is not
           locked, it can be interrupted by another handling path.
             =================================================================
             (event pending A)
             =================================================================
             acpi_ev_gpe_detect()        ec_poll()
               if (EN==1 && STS==1)
             *****************************************************************
             (event handling A)
                                           Lock(EC)
                                           advance_transaction()
                                             EC_SC read
                                             EC_SC handled
                                           Unlock(EC)
             *****************************************************************
               acpi_ev_gpe_dispatch()
                 EN=0
                 STS=0
                 acpi_ec_gpe_handler()
             *****************************************************************
             (event handling B)
                   Lock(EC)
                   advance_transaction()
                     EC_SC read
                   Unlock(EC)
             *****************************************************************
            3. Issue 3:
               We can see no-op acpi_ec_gpe_handler() invoked on both silicon
               variation A and B. This is because:
               a. event pending A: An event can arrive to trigger an EC GPE and
                  ACPICA checks it and is about to invoke the EC GPE handler;
               b. event handling A: The event can be handled in ec_poll() because
                  EC lock is not held after the GPE status checking;
               c. event handling B: Then when the EC GPE handler is invoked, it
                  becomes a no-op GPE handler invocation.
               d. As no-op GPE handler invocations are counted by the EC driver
                  to trigger the command storming conditions, the wrong no-op
                  GPE handler invocations thus can easily trigger wrong command
                  storming conditions.
            Note 3:
            This no-op GPE handler invocation is rare because the time between
            the IRQ arrival and the acpi_ec_gpe_handler() invocation is less than
            the timeout value waited in ec_poll(). So most of the no-op GPE
            handler invocations are caused by the reason described in issue 1.
      3. There is a race condition due to ACPICA internal GPE clearing logic in
         acpi_enable_gpe():
           During runtime, acpi_enable_gpe() can be invoked by the EC storming
           prevention code. When it is invoked, GPE may be flagged (STS=1).
             =================================================================
             (event pending A)
             =================================================================
             acpi_ev_gpe_dispatch()    acpi_ec_transaction()
               EN=0
               STS=0
               acpi_ec_gpe_handler()
             *****************************************************************
             (event handling A)
                 Lock(EC)
                 advance_transaction()
                   EC_SC read
                   EC_SC handled
                 Unlock(EC)
             *****************************************************************
               EN=1 ?
                                         Lock(EC)
                                         Unlock(EC)
             =================================================================
             (event pending B)
             =================================================================
                                         acpi_enable_gpe()
                                           STS=0
                                           EN=1
          4. Issue 4:
             We can see GPE loss on both silicon variation A and B platforms.
             This is because:
             a. event pending B: An event can arrive right before ACPICA's GPE
                clearing performed in acpi_enable_gpe();
             b. If the GPE is cleared when GPE is disabled, then EN=1 write in
                acpi_enable_gpe() cannot trigger this GPE;
             c. If no polling mechanism is implemented in the driver for this
                event (for example, SCI_EVT), this event is lost due to no GPE
                being triggered.
             Note 4:
             Currently we don't have this issue, but after we switch the EC
             driver into ACPI_GPE_DISPATCH_RAW_HANDLER mode, we need to take care
             of handling this because the EN=1 write in acpi_ev_gpe_dispatch()
             will be abandoned.
      
      There might be more race issues for the current GPE handler usages. This is
      because the EC IRQ's enabling/disabling/checking/clearing/handling
      operations should be locked by a single lock that is under the EC driver's
      control to achieve the serialization. Which means we need to invoke GPE
      APIs with EC driver's lock held and all ACPICA internal GPE operations
      related to the GPE handler should be abandoned. Invoking GPE APIs inside of
      the EC driver lock and bypassing ACPICA internal GPE operations requires
      the ACPI_GPE_DISPATCH_RAW_HANDLER mode where the same lock used by the APIs
      are released prior than invoking the handlers. Otherwise, we can see dead
      locks due to circular locking dependencies (see Reference below).
      
      This patch then switches the EC driver into the
      ACPI_GPE_DISPATCH_RAW_HANDLER mode so that it can perform correct GPE
      operations using the GPE APIs:
      1. Bypasses EN modifications performed in acpi_ev_gpe_dispatch() by
         using acpi_install_gpe_raw_handler() and invoking all GPE APIs with EC
         spin lock held. This can fix issue 1 as it makes a non frequent GPE
         enabling/disabling environment.
      2. Bypasses STS clearing performed in acpi_enable_gpe() by replacing
         acpi_enable_gpe()/acpi_disable_gpe() with acpi_set_gpe(). This can fix
         issue 4. And this can also help to fix issue 1 as it makes a no sudden
         GPE clearing environment when GPE is frequently enabled/disabled.
      3. Ensures STS acknowledged before handling by invoking acpi_clear_gpe()
         in advance_transaction(). This can finally fix issue 1 even in a
         frequent GPE enabling/disabling environment. And this can also finally
         fix issue 3 when issue 2 is fixed.
         Note 3:
         GPE clearing is edge triggered W1C, which means we can clear it right
         before handling it. Since all EC GPE indications are handled in
         advance_transaction() by previous commits, we can now move GPE clearing
         into it to implement the correct GPE clearing.
         Note 4:
         We can use acpi_set_gpe() which is not shared GPE safer instead of
         acpi_enable_gpe()/acpi_disable_gpe() because EC GPE is not shared by
         other hardware, which is mentioned in the ACPI specification 5.0, 12.6
         Interrupt Model: "OSPM driver treats this as an edge event (the EC SCI
         cannot be shared)". So we can stop using shared GPE safer APIs
         acpi_enable_gpe()/acpi_disable_gpe() in the EC driver. Otherwise
         cleanups need to be made in acpi_ev_enable_gpe() to bypass the GPE
         clearing logic before keeping acpi_enable_gpe().
      This patch also invokes advance_transaction() when GPE is re-enabled in the
      task context which:
      1. Ensures EN=1 can trigger GPE by checking and handling EC status register
         right after EN=1 writes. This can fix issue 2.
      
      After applying this patch, without frequent GPE enablings considered:
             =================================================================
             (event pending A)
             =================================================================
             acpi_ec_gpe_handler()     ec_poll()
             *****************************************************************
             (event handling A)
               Lock(EC)
                 advance_transaction()
                   if STS==1
                     STS=0
                   EC_SC read
             =================================================================
             (event pending B)
             =================================================================
                   EC_SC handled
               Unlock(EC)
             *****************************************************************
             *****************************************************************
             (event handling B)
                                         Lock(EC)
                                           advance_transaction()
                                             if STS==1
                                               STS=0
                                             EC_SC read
             =================================================================
             (event pending C)
             =================================================================
                                             EC_SC handled
                                         Unlock(EC)
             *****************************************************************
      The event pending for issue 1 (event pending B) can arrive as a next GPE
      due to the previous IRQ context STS=0 write. And if it is handled by
      ec_poll() (event handling B), as it is also acknowledged by ec_poll(), the
      event pending for issue 2 (event pending C) can properly arrive as a next
      GPE after the task context STS=0 write. So no GPE will be lost and never
      triggered due to GPE clearing performed in the wrong position. And since
      all GPE handling is performed after a locked GPE status checking, we can
      hardly see no-op GPE handler invocations due to issue 1 and 3. We may still
      see no-op GPE handler invocations due to "Note 1", but as it is inevitable,
      it needn't be fixed.
      
      After applying this patch, with frequent GPE enablings considered:
             =================================================================
             (event pending A)
             =================================================================
             acpi_ec_gpe_handler()     acpi_ec_transaction()
             *****************************************************************
             (event handling A)
               Lock(EC)
                 advance_transaction()
                   if STS==1
                     STS=0
                   EC_SC read
             =================================================================
             (event pending B)
             =================================================================
                   EC_SC handled
               Unlock(EC)
             *****************************************************************
             *****************************************************************
             (event handling B)
                                         Lock(EC)
                                           EN=1
                                           if STS==1
                                             advance_transaction()
                                               if STS==1
                                                 STS=0
                                               EC_SC read
             =================================================================
             (event pending C)
             =================================================================
                                               EC_SC handled
                                         Unlock(EC)
             *****************************************************************
      The event pending for issue 2 can be manually handled by
      advance_transaction(). And after the STS=0 write performed in the manual
      triggered advance_transaction(), GPE can always arrive. So no GPE will be
      lost due to frequent GPE disabling/enabling performed in the driver like
      issue 4.
      Note 5:
      It's ideally when EN=1 write occurred, an IRQ thread should be woken up to
      handle the GPE when the GPE was raised. But this requires the IRQ thread to
      contain the poller code for all EC GPE indications, while currently some of
      the indications are handled in the user tasks. It then is very hard for the
      code to determine whether a user task should be invoked or the poller work
      item should be scheduled. So we have to invoke advance_transaction()
      directly now and it leaves us such a restriction for the GPE re-enabling:
      it must be performed in the task context to avoid starving the GPEs.
      
      As a conclusion: we can see the EC GPE is always handled in serial after
      deploying the raw GPE handler mode:
        Lock(EC)
        if (STS==1)
          STS=0
        EC_SC read
        EC_SC handled
        Unlock(EC)
      The EC driver specific lock is responsible to make the EC GPE handling
      processes serialized so that EC can handle its GPE from both IRQ and task
      contexts and the next IRQ can be ensured to arrive after this process.
      
      Note 6:
      We have many EC_FLAGS_MSI qurik users in the current driver. They all seem
      to be suffering from unexpected GPE triggering source lost. And they are
      false root caused to a timing issue. Since EC communication protocol has
      already flow control defined, timing shouldn't be the root cause, while
      this fix might be fixing the root cause of the old bugs.
      
      Link: https://lkml.org/lkml/2014/11/4/974
      Link: https://lkml.org/lkml/2014/11/18/316
      Link: https://www.spinics.net/lists/linux-acpi/msg54340.htmlSigned-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      ca37bfdf
    • Rafael J. Wysocki's avatar
      Merge branch 'acpica' into acpi-ec · 38220a5e
      Rafael J. Wysocki authored
      38220a5e
    • Lv Zheng's avatar
      ACPICA: Events: Enable APIs to allow interrupt/polling adaptive request based GPE handling model · 2eedd3d8
      Lv Zheng authored
      ACPICA commit da9a83e1a845f2d7332bdbc0632466b2595e5424
      
      For acpi_set_gpe()/acpi_enable_gpe(), our target is to purify them to be APIs
      that can be used for various GPE handling models, so we need them to be
      pure GPE enabling APIs. GPE enabling/disabling has 2 use cases:
      1. Driver may permanently enable/disable GPEs according to the usage
         counts.
         1. When upper layers (the users of the driver) submit requests to the
            driver, it means they care about the underlying hardware. GPE need
            to be enabled for the first request submission and disabled for the
            last request completion.
         2. When the GPE is shared between 2+ silicon logics. GPE need to be
            enabled for either silicon logic's driver and disabled when all of
            the drivers are not started.
         For these cases, acpi_enable_gpe()/acpi_disable_gpe() should be used. When
         the usage count is increased from 0 to 1, the GPE is enabled and it is
         disabled when the usage count is decrased from 1 to 0.
      2. Driver may temporarily disables the GPE to enter an GPE polling mode and
         wants to re-enable it later.
         1. Prevent GPE storming: when a driver cannot fully solve the condition
            that triggered the GPE in the GPE context, in order not to trigger
            GPE storm, driver has to disable GPE to switch into the polling mode
            and re-enables it in the non interrupt context after the storming
            condition is cleared.
         2. Meet throughput requirement: some IO drivers need to poll hardware
            again and again until nothing indicated instead of just handling once
            for one interruption, this need to be done in the polling mode or the
            IO flood may prevent the GPE handler from returning.
         3. Meet realtime requirement: in order not to block CPU to handle higher
            realtime prioritized GPEs, lower priority GPEs can be handled in the
            polling mode.
         For these cases, acpi_set_gpe() should be used to switch to/from the
         polling mode.
      
      This patch adds unconditional GPE enabling support into acpi_set_gpe() so
      that this API can be used by the drivers to switch back from the GPE
      polling mode unconditionally.
      
      Originally this function includes GPE clearing logic in it.
      First, the GPE clearing is typically used in the GPE handling code to:
      1. Acknowledge the GPE when we know there is an edge triggered GPE raised
         and is about to handle it, otherwise the unexpected clearing may lead to
         a GPE loss;
      2. Issue actions after we have handled a level triggered GPE, otherwise
         the unexpected clearing may trigger unwanted OSPM actions to the
         hardware (for example, clocking in out-dated write FIFO data).
      Thus the GPE clearing is not suitable to be used in the GPE enabling APIs.
      Second, the combination of acknowledging and enabling may also not be
      expected by the hardware drivers. For GPE clearing, we have a seperate API
      acpi_clear_gpe(). There are cases drivers do want the 2 operations to be
      split. So splitting these 2 operations could facilitates drivers the
      maximum possibilities to achieve success. For a combined one, we already
      have acpi_finish_gpe() ready to be invoked.
      
      Given the fact that drivers should complete all outstanding requests before
      putting themselves into the sleep states, as this API is executed for
      outstanding requests, it should also have nothing to do with the
      "RUN"/"WAKE" distinguishing. That's why the acpi_set_gpe(ACPI_GPE_ENABLE)
      should not be implemented by acpi_hw_low_set_gpe(ACPI_GPE_CONDITIONAL_ENABLE).
      
      This patch thus converts acpi_set_gpe(ACPI_GPE_ENABLE) into
      acpi_hw_low_set_gpe(ACPI_GPE_ENABLE) to achieve a seperate GPE enabling API.
      Drivers then are encouraged to use this API when they need to switch
      to/from the GPE polling mode.
      
      Note that the acpi_set_gpe()/acpi_finish_gpe() should be first introduced to
      Linux using a divergence reduction patch before sending a linuxized version
      of this patch. Lv Zheng.
      
      Link: https://github.com/acpica/acpica/commit/da9a83e1Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      2eedd3d8
    • Lv Zheng's avatar
      ACPICA: Events: Introduce acpi_set_gpe()/acpi_finish_gpe() to reduce divergences · eb3d80f7
      Lv Zheng authored
      This can help to reduce source code differences between Linux and ACPICA
      upstream. Further driver cleanups also require these APIs to eliminate GPE
      storms.
      1. acpi_set_gpe(): An API that driver should invoke in the case it wants
                         to disable/enable IRQ without honoring the reference
                         count implemented in the acpi_disable_gpe() and
                         acpi_enable_gpe(). Note that this API should only be
                         invoked inside a acpi_enable_gpe()/acpi_disable_gpe()
                         pair.
      2. acpi_finish_gpe(): Drivers returned ACPI_REENABLE_GPE unset from the
                            GPE handler should use this API instead of
                            invoking acpi_set_gpe()/acpi_enable_gpe() to
                            re-enable the GPE.
      The GPE APIs can be invoked inside of a GPE handler or in the task context
      with a driver provided lock held. This driver provided lock is safe to be
      held in the GPE handler by the driver.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      eb3d80f7
    • Lv Zheng's avatar
      ACPICA: Events: Introduce ACPI_GPE_DISPATCH_RAW_HANDLER to fix 2 issues for the current GPE APIs · 0d0988af
      Lv Zheng authored
      ACPICA commit 199cad16530a45aea2bec98e528866e20c5927e1
      
      Since whether the GPE should be disabled/enabled/cleared should only be
      determined by the GPE driver's state machine:
      1. GPE should be disabled if the driver wants to switch to the GPE polling
         mode when a GPE storm condition is indicated and should be enabled if
         the driver wants to switch back to the GPE interrupt mode when all of
         the storm conditions are cleared. The conditions should be protected by
         the driver's specific lock.
      2. GPE should be enabled if the driver has accepted more than one request
         and should be disabled if the driver has completed all of the requests.
         The request count should be protected by the driver's specific lock.
      3. GPE should be cleared either when the driver is about to handle an edge
         triggered GPE or when the driver has completed to handle a level
         triggered GPE. The handling code should be protected by the driver's
         specific lock.
      Thus the GPE enabling/disabling/clearing operations are likely to be
      performed with the driver's specific lock held while we currently cannot do
      this. This is because:
      1. We have the acpi_gbl_gpe_lock held before invoking the GPE driver's
         handler. Driver's specific lock is likely to be held inside of the
         handler, thus we can see some dead lock issues due to the reversed
         locking order or recursive locking. In order to solve such dead lock
         issues, we need to unlock the acpi_gbl_gpe_lock before invoking the
         handler. BZ 1100.
      2. Since GPE disabling/enabling/clearing should be determined by the GPE
         driver's state machine, we shouldn't perform such operations inside of
         ACPICA for a GPE handler to mess up the driver's state machine. BZ 1101.
      
      Originally this patch includes a logic to flush GPE handlers, it is dropped
      due to the following reasons:
      1. This is a different issue;
      2. Linux OSL has fixed this by flushing SCI in acpi_os_wait_events_complete().
      We will pick up this topic when the Linux OSL fix turns out to be not
      sufficient.
      
      Note that currently the internal operations and the acpi_gbl_gpe_lock are
      also used by ACPI_GPE_DISPATCH_METHOD and ACPI_GPE_DISPATCH_NOTIFY. In
      order not to introduce regressions, we add one
      ACPI_GPE_DISPATCH_RAW_HANDLER type to be distiguished from
      ACPI_GPE_DISPATCH_HANDLER. For which the acpi_gbl_gpe_lock is unlocked before
      invoking the GPE handler and the internal enabling/disabling operations are
      bypassed to allow drivers to perform them at a proper position using the
      GPE APIs and ACPI_GPE_DISPATCH_RAW_HANDLER users should invoke acpi_set_gpe()
      instead of acpi_enable_gpe()/acpi_disable_gpe() to bypass the internal GPE
      clearing code in acpi_enable_gpe(). Lv Zheng.
      
      Known issues:
      1. Edge-triggered GPE lost for frequent enablings
         On some buggy silicon platforms, GPE enable line may not be directly
         wired to the GPE trigger line. In that case, when GPE enabling is
         frequently performed for edge-triggered GPEs, GPE status may stay set
         without being triggered.
         This patch may maginify this problem as it allows GPE enabling to be
         parallel performed during the process the GPEs are handled.
         This is an existing issue, because:
         1. For task context:
            Current ACPI_GPE_DISPATCH_METHOD practices have proven that this
            isn't a real issue - we can re-enable edge-triggered GPE in a work
            queue where the GPE status bit might already be set.
         2. For IRQ context:
            This can even happen when the GPE enabling occurs before returning
            from the GPE handler and after unlocking the GPE lock.
         Thus currently no code is included to protect this.
      
      Link: https://github.com/acpica/acpica/commit/199cad16Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      0d0988af
    • David E. Box's avatar
      ACPICA: Update version to 20150204 · 121b7d91
      David E. Box authored
      ACPICA commit e06b1624b02dc8317d144e9a6fe9d684c5fa2f90
      
      Version 20150204.
      
      Link: https://github.com/acpica/acpica/commit/e06b1624Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      121b7d91
    • David E. Box's avatar
      ACPICA: Update Copyright headers to 2015 · 82a80941
      David E. Box authored
      ACPICA commit 8990e73ab2aa15d6a0068b860ab54feff25bee36
      
      Link: https://github.com/acpica/acpica/commit/8990e73aSigned-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      82a80941
    • David E. Box's avatar
      ACPICA: Hardware: Cast GPE enable_mask before storing · d6c02669
      David E. Box authored
      ACPICA commit 490ec7f7839bf7ee5e8710a34d1d1a78d54a49b6
      
      In function acpi_hw_low_set_gpe(), cast enable_mask to u8 before
      storing. The mask was read from a 32 bit register but is an 8 bit
      value. Fixes Visual Studio compiler warning.
      
      Link: https://github.com/acpica/acpica/commit/490ec7f7Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      d6c02669
    • Lv Zheng's avatar
      ACPICA: Events: Cleanup GPE dispatcher type obtaining code · 7c43312a
      Lv Zheng authored
      ACPICA commit 7926d5ca9452c87f866938dcea8f12e1efb58f89
      
      There is an issue in acpi_install_gpe_handler() and acpi_remove_gpe_handler().
      The code to obtain the GPE dispatcher type from the Handler->original_flags
      is wrong:
          if (((Handler->original_flags & ACPI_GPE_DISPATCH_METHOD) ||
               (Handler->original_flags & ACPI_GPE_DISPATCH_NOTIFY)) &&
      ACPI_GPE_DISPATCH_NOTIFY is 0x03 and ACPI_GPE_DISPATCH_METHOD is 0x02, thus
      this statement is TRUE for the following dispatcher types:
          0x01 (ACPI_GPE_DISPATCH_HANDLER): not expected
          0x02 (ACPI_GPE_DISPATCH_METHOD): expected
          0x03 (ACPI_GPE_DISPATCH_NOTIFY): expected
      
      There is no functional issue due to this because Handler->original_flags is
      only set in acpi_install_gpe_handler(), and an earlier checker has excluded
      the ACPI_GPE_DISPATCH_HANDLER:
          if ((gpe_event_info->Flags & ACPI_GPE_DISPATCH_MASK) ==
                  ACPI_GPE_DISPATCH_HANDLER)
          {
              Status = AE_ALREADY_EXISTS;
              goto free_and_exit;
          }
          ...
          Handler->original_flags = (u8) (gpe_event_info->Flags &
              (ACPI_GPE_XRUPT_TYPE_MASK | ACPI_GPE_DISPATCH_MASK));
      
      We need to clean this up before modifying the GPE dispatcher type values.
      
      In order to prevent such issue from happening in the future, this patch
      introduces ACPI_GPE_DISPATCH_TYPE() macro to be used to obtain the GPE
      dispatcher types. Lv Zheng.
      
      Link: https://github.com/acpica/acpica/commit/7926d5caSigned-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      7c43312a
    • Lv Zheng's avatar
      ACPICA: Events: Cleanup to move acpi_gbl_global_event_handler invocation out... · 779ba5a3
      Lv Zheng authored
      ACPICA: Events: Cleanup to move acpi_gbl_global_event_handler invocation out of acpi_ev_gpe_dispatch()
      
      ACPICA commit 04f25acdd4f655ae33f83de789bb5f4b7790171c
      
      This patch follows acpi_ev_fixed_event_detect(), which invokes
      acpi_gbl_global_event_handler instead of invoking it in
      acpi_ev_fixed_event_dispatch(), moves acpi_gbl_global_event_handler from
      acpi_ev_gpe_dispatch() to acpi_ev_gpe_detect(). This makes further cleanups
      around acpi_ev_gpe_dispatch() simpler. Lv Zheng.
      
      Link: https://github.com/acpica/acpica/commit/04f25acdSigned-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      779ba5a3
    • Lv Zheng's avatar
      ACPICA: Events: Cleanup of resetting the GPE handler to NULL before removing · c539251e
      Lv Zheng authored
      ACPICA commit b2b18bb38045404e253f10787b8a4ae6e94cdee6
      
      This patch prevents acpi_remove_gpe_handler() from leaking the stale
      gpe_event_info->Dispatch.Handler to the caller to avoid possible NULL pointer
      references. Lv Zheng.
      
      Link: https://github.com/acpica/acpica/commit/b2b18bb3Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      c539251e
    • David E. Box's avatar
      ACPICA: Events: Fix uninitialized variable · b7be6883
      David E. Box authored
      ACPICA commit 8e21180050270897499652e922c6a41b8eb388b6
      
      Recent changes to acpi_ev_asynch_execute_gpe_method left Status
      variable uninitialized before use. Initialize to AE_OK.
      
      Link: https://github.com/acpica/acpica/commit/8e211800Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      b7be6883
    • Lv Zheng's avatar
      ACPICA: Events: Remove acpi_ev_valid_gpe_event() due to current restriction · b18da580
      Lv Zheng authored
      ACPICA commit 8823b44ff53859ab24ecfcfd3fba8cc56b17d223
      
      Currently we rely on the logic that GPE blocks will never be deleted,
      otherwise we can be broken by the race between acpi_ev_create_gpe_block(),
      acpi_ev_delete_gpe_block() and acpi_ev_gpe_detect().
      On the other hand, if we want to protect GPE block creation/deletion, we
      need to use a different synchronization facility to protect the period
      between acpi_ev_gpe_dispatch() and acpi_ev_asynch_enable_gpe(). Which leaves us
      no choice but abandoning the ACPI_MTX_EVENTS used during this period.
      
      This patch removes ACPI_MTX_EVENTS used during this period and the
      acpi_ev_valid_gpe_event() to reflect current restriction. Lv Zheng.
      
      Link: https://github.com/acpica/acpica/commit/8823b44fSigned-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      b18da580
    • Lv Zheng's avatar
      ACPICA: Events: Remove duplicated sanity check in acpi_ev_enable_gpe() · 833bb931
      Lv Zheng authored
      ACPICA commit ca10324788bc9bdaf47fa9e51145129c1299144d
      
      This patch deletes a sanity check from acpi_ev_enable_gpe().
      
      This kind of check is already done in
      acpi_enable_gpe()/acpi_remove_gpe_handler()/acpi_update_all_gpes() before invoking
      acpi_ev_enable_gpe():
      1. acpi_enable_gpe(): same check (skip if DISPATCH_NONE) is now implemented.
      2. acpi_remove_gpe_handler(): a more strict check (skip if !DISPATCH_HANDLER)
                                 is implemented.
      3. acpi_update_all_gpes(): a more strict check (skip if DISPATCH_NONE ||
                              DISPATCH_HANDLER || CAN_WAKE)
      4. acpi_set_gpe(): since it is invoked by the OSPM driver where the GPE
                       handler is known to be available, such check isn't needed.
      So we can simply remove this duplicated check from acpi_ev_enable_gpe().
      Lv Zheng.
      
      Link: https://github.com/acpica/acpica/commit/ca103247Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarDavid E. Box <david.e.box@linux.intel.com>
      Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      833bb931
    • Lv Zheng's avatar
      ACPICA: Events: Back port "ACPICA: Save current masks of enabled GPEs after enable register writes" · 1c4c81a2
      Lv Zheng authored
      This is a back port result of the Linux commit:
        Commit c50f13c6
        Subject: ACPICA: Save current masks of enabled GPEs after enable register writes
      
      Besides of the indent divergences, only a missing prototype added due to
      the ACPICA internal coding style.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      1c4c81a2
  3. 26 Jan, 2015 2 commits
  4. 23 Jan, 2015 6 commits
    • Lv Zheng's avatar
      ACPI / EC: Cleanup QR_EC related code · 550b3aac
      Lv Zheng authored
      The QR_EC related code pieces have redundants, this patch merges them into
      acpi_ec_query() which invokes acpi_ec_transaction() where EC mutex and the
      global lock are already held. After doing so, query handler traversal still
      need to be locked by EC mutex after invoking acpi_ec_transaction().
      
      Note that EC event handling is sequential. We fetch one event from firmware
      event queue and process it until 0x00 or error returned. So we don't need
      to hold mutex for whole acpi_ec_clear() process to determine whether we
      should continue to drain. And for the same reason, we don't need to hold
      mutex for the whole procedure from the QR_EC transaction to the query
      handler traversal.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      550b3aac
    • Lv Zheng's avatar
      ACPI / EC: Fix issues related to the SCI_EVT handling · 74443bbe
      Lv Zheng authored
      This patch fixes 2 issues related to the draining behavior. But it doesn't
      implement the draining support, it only cleans up code so that further
      draining support is possible.
      
      The draining behavior is expected by some platforms (for example, Samsung)
      where SCI_EVT is set only once for a set of events and might be cleared for
      the very first QR_EC command issued after SCI_EVT is set. EC firmware on
      such platforms will return 0x00 to indicate "no outstanding event". Thus
      after seeing an SCI_EVT indication, EC driver need to fetch events until
      0x00 returned (see acpi_ec_clear()).
      
      Issue 1 - acpi_ec_submit_query():
      It's reported on Samsung laptops that SCI_EVT isn't checked when the
      transactions are advanced in ec_poll(), which leads to SCI_EVT triggering
      source lost:
       If no EC GPE IRQs are arrived after that, EC driver cannot detect this
       event and handle it.
      See comment 244/247 for kernel bugzilla 44161.
      This patch fixes this issue by moving SCI_EVT checks into
      advance_transaction(). So that SCI_EVT is checked each time we are going to
      handle the EC firmware indications. And this check will happen for both IRQ
      context and task context.
      Since after doing that, SCI_EVT is also checked after completing a
      transaction, ec_check_sci() and ec_check_sci_sync() can be removed.
      
      Issue 2 - acpi_ec_complete_query():
      We expect to clear EC_FLAGS_QUERY_PENDING to allow queuing another draining
      QR_EC after writing a QR_EC command and before reading the event. After
      reading the event, SCI_EVT might be cleared by the firmware, thus it may
      not be possible to queue such a draining QR_EC at that time.
      But putting the EC_FLAGS_QUERY_PENDING clearing code after
      start_transaction() is wrong as there are chances that after
      start_transaction(), QR_EC can fail to be sent. If this happens,
      EC_FLAG_QUERY_PENDING will be cleared earlier. As a consequence, the
      draining QR_EC will also be queued earlier than expected.
      This patch also moves this code into advance_transaction() where QR_EC is
      just sent (ACPI_EC_COMMAND_POLL flagged) to fix this issue.
      
      Notes:
      1. After introducing the 2 SCI_EVT related handlings into
         advance_transaction(), a next QR_EC can be queued right after writing
         the current QR_EC command and before reading the event. But this still
         hasn't implemented the draining behavior as the draining support
         requires:
           If a previous returned event value isn't 0x00, a draining QR_EC need
           to be issued even when SCI_EVT isn't set.
      2. In this patch, acpi_os_execute() is also converted into a seperate work
         item to avoid invoking kmalloc() in the atomic context. We can do this
         because of the previous global lock fix.
      3. Originally, EC_FLAGS_EVENT_PENDING is also used to avoid queuing up
         multiple work items (created by acpi_os_execute()), this can be covered
         by only using a single work item. But this patch still keeps this flag
         as there are different usages in the driver initialization steps relying
         on this flag.
      
      Link: https://bugzilla.kernel.org/show_bug.cgi?id=44161Reported-by: default avatarKieran Clancy <clancy.kieran@gmail.com>
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      74443bbe
    • Lv Zheng's avatar
      ACPI / EC: Fix a code path that global lock is not held · f3e14329
      Lv Zheng authored
      Currently QR_EC is queued up on CPU 0 to be safe with SMM because there is
      no global lock held for acpi_ec_gpe_query(). As we are about to move QR_EC
      to a non CPU 0 bound work queue to avoid invoking kmalloc() in
      advance_transaction(), we have to acquire global lock for the new QR_EC
      work item to avoid regressions.
      
      Known issue:
      1. Global lock for acpi_ec_clear().
         This is an existing issue that acpi_ec_clear() which invokes
         acpi_ec_sync_query() also suffers from the same issue. But this patch's
         target is only the code to invoke acpi_ec_sync_query() in a CPU 0 bound
         work queue item, and the acpi_ec_clear() can be automatically fixed by
         further patch that merges the redundant code, so it is left unchanged.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      f3e14329
    • Lv Zheng's avatar
      ACPI / EC: Fix returning values in acpi_ec_sync_query() · c2cf5769
      Lv Zheng authored
      The returning value of acpi_os_execute() is erroneously handled as errno.
      This patch corrects it by returning EBUSY to indicate the work queue item
      creation failure.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      c2cf5769
    • Lv Zheng's avatar
      ACPI / EC: Add reference counting for query handlers · 01305d41
      Lv Zheng authored
      This patch adds reference counting for query handlers in order to eliminate
      kmalloc()/kfree() usage.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Tested-by: default avatarSteffen Weber <steffen.weber@gmail.com>
      Tested-by: default avatarOrtwin Glück <odi@odi.ch>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      01305d41
    • Lv Zheng's avatar
      ACPI / EC: Cleanup transaction wakeup code · 0c78808f
      Lv Zheng authored
      This patch moves transaction wakeup code into advance_transaction().
      No functional changes.
      Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
      Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      0c78808f
  5. 22 Jan, 2015 1 commit
  6. 18 Jan, 2015 4 commits
    • Linus Torvalds's avatar
      Linux 3.19-rc5 · ec6f34e5
      Linus Torvalds authored
      ec6f34e5
    • Linus Torvalds's avatar
      Merge tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc · d0ac5d8e
      Linus Torvalds authored
      Pull ARM SoC fixes from Olof Johansson:
       "We've been sitting on our fixes branch for a while, so this batch is
        unfortunately on the large side.
      
        A lot of these are tweaks and fixes to device trees, fixing various
        bugs around clocks, reg ranges, etc.  There's also a few defconfig
        updates (which are on the late side, no more of those).
      
        All in all the diffstat is bigger than ideal at this time, but nothing
        in here seems particularly risky"
      
      * tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (31 commits)
        reset: sunxi: fix spinlock initialization
        ARM: dts: disable CCI on exynos5420 based arndale-octa
        drivers: bus: check cci device tree node status
        ARM: rockchip: disable jtag/sdmmc autoswitching on rk3288
        ARM: nomadik: fix up leftover device tree pins
        ARM: at91: board-dt-sama5: add phy_fixup to override NAND_Tree
        ARM: at91/dt: sam9263: Add missing clocks to lcdc node
        ARM: at91: sama5d3: dt: correct the sound route
        ARM: at91/dt: sama5d4: fix the timer reg length
        ARM: exynos_defconfig: Enable LM90 driver
        ARM: exynos_defconfig: Enable options for display panel support
        arm: dts: Use pmu_system_controller phandle for dp phy
        ARM: shmobile: sh73a0 legacy: Set .control_parent for all irqpin instances
        ARM: dts: berlin: correct BG2Q's SM GPIO location.
        ARM: dts: berlin: add broken-cd and set bus width for eMMC in Marvell DMP DT
        ARM: dts: berlin: fix io clk and add missing core clk for BG2Q sdhci2 host
        ARM: dts: Revert disabling of smc91x for n900
        ARM: dts: imx51-babbage: Fix ULPI PHY reset modelling
        ARM: dts: dra7-evm: fix qspi device tree partition size
        ARM: omap2plus_defconfig: use CONFIG_CPUFREQ_DT
        ...
      d0ac5d8e
    • Linus Torvalds's avatar
      Merge tag 'clk-fixes-for-linus' of git://git.linaro.org/people/mike.turquette/linux · 12ba8571
      Linus Torvalds authored
      Pull clock driver fixes from Mike Turquette:
       "Small number of fixes for clock drivers and a single null pointer
        dereference fix in the framework core code.
      
        The driver fixes vary from fixing section mismatch warnings to
        preventing machines from hanging (and preventing developers from
        crying)"
      
      * tag 'clk-fixes-for-linus' of git://git.linaro.org/people/mike.turquette/linux:
        clk: fix possible null pointer dereference
        Revert "clk: ppc-corenet: Fix Section mismatch warning"
        clk: rockchip: fix deadlock possibility in cpuclk
        clk: berlin: bg2q: remove non-exist "smemc" gate clock
        clk: at91: keep slow clk enabled to prevent system hang
        clk: rockchip: fix rk3288 cpuclk core dividers
        clk: rockchip: fix rk3066 pll lock bit location
        clk: rockchip: Fix clock gate for rk3188 hclk_emem_peri
        clk: rockchip: add CLK_IGNORE_UNUSED flag to fix rk3066/rk3188 USB Host
      12ba8571
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 901b2082
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "This is one fix for a Multiqueue sleeping in invalid context problem
        and a MAINTAINER file update for Qlogic"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: ->queue_rq can't sleep
        MAINTAINERS: Update maintainer list for qla4xxx
      901b2082
  7. 17 Jan, 2015 9 commits