1. 19 Jun, 2017 1 commit
  2. 13 Jun, 2017 3 commits
  3. 08 Jun, 2017 1 commit
  4. 07 Jun, 2017 13 commits
    • Ville Syrjälä's avatar
      drm/i915: Fix 90/270 rotated coordinates for FBC · 1065467e
      Ville Syrjälä authored
      The clipped src coordinates have already been rotated by 270 degrees for
      when the plane rotation is 90/270 degrees, hence the FBC code should no
      longer swap the width and height.
      
      Cc: stable@vger.kernel.org
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
      Fixes: b63a16f6 ("drm/i915: Compute display surface offset in the plane check hook for SKL+")
      Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170331180056.14086-4-ville.syrjala@linux.intel.comReviewed-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
      Tested-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
      Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
      (cherry picked from commit 73714c05)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      1065467e
    • Ville Syrjälä's avatar
      drm/i915: Restore has_fbc=1 for ILK-M · 27fe407c
      Ville Syrjälä authored
      Restore the lost has_fbc flag for mobile ILK.
      
      Cc: Carlos Santa <carlos.santa@intel.com>
      Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
      Fixes: a1323380 ("drm/i915: Introduce GEN5_FEATURES for device info")
      Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170606133229.12439-1-ville.syrjala@linux.intel.comReviewed-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      (cherry picked from commit c2d1a0ce)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      27fe407c
    • Ville Syrjälä's avatar
      drm/i915: Workaround VLV/CHV DSI scanline counter hardware fail · 8f4d3809
      Ville Syrjälä authored
      The scanline counter is bonkers on VLV/CHV DSI. The scanline counter
      increment is not lined up with the start of vblank like it is on
      every other platform and output type. This causes problems for
      both the vblank timestamping and atomic update vblank evasion.
      
      On my FFRD8 machine at least, the scanline counter increment
      happens about 1/3 of a scanline ahead of the start of vblank (which
      is where all register latching happens still). That means we can't
      trust the scanline counter to tell us whether we're in vblank or not
      while we're on that particular line. In order to keep vblank
      timestamping in working condition when called from the vblank irq,
      we'll leave scanline_offset at one, which means that the entire
      line containing the start of vblank is considered to be inside
      the vblank.
      
      For the vblank evasion we'll need to consider that entire line
      to be bad, since we can't tell whether the registers already
      got latched or not. And we can't actually use the start of vblank
      interrupt to get us past that line as the interrupt would fire
      too soon, and then we'd up waiting for the next start of vblank
      instead. One way around that would using the frame start
      interrupt instead since that wouldn't fire until the next
      scanline, but that would require some bigger changes in the
      interrupt code. So for simplicity we'll just poll until we get
      past the bad line.
      
      v2: Adjust the comments a bit
      
      Cc: stable@vger.kernel.org
      Cc: Jonas Aaberg <cja@gmx.net>
      Tested-by: default avatarJonas Aaberg <cja@gmx.net>
      Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99086Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20161215174734.28779-1-ville.syrjala@linux.intel.comTested-by: default avatarMika Kahola <mika.kahola@intel.com>
      Reviewed-by: default avatarMika Kahola <mika.kahola@intel.com>
      (cherry picked from commit ec1b4ee2)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      8f4d3809
    • Chris Wilson's avatar
      drm/i915: Fix logical inversion for gen4 quirking · 5857dbfa
      Chris Wilson authored
      The assertion that we want to make before disabling the pin of the pages
      for the unknown swizzling quirk is that the quirk is indeed active, and
      that the quirk is disabled before we do apply it to the pages.
      
      Fixes: 2c3a3f44 ("drm/i915: Fix pages pin counting around swizzle quirk")
      Fixes: 957870f9 ("drm/i915: Split out i915_gem_object_set_tiling()")
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Cc: Chris Wilson <chris@chris-wilson.co.uk>
      Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170521124014.27678-1-chris@chris-wilson.co.uk
      Reviewed-bhy: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
      (cherry picked from commit 20bb3771)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      5857dbfa
    • Chris Wilson's avatar
      drm/i915: Guard against i915_ggtt_disable_guc() being invoked unconditionally · d90c9890
      Chris Wilson authored
      Commit 7c3f86b6 ("drm/i915: Invalidate the guc ggtt TLB upon
      insertion") added the restoration of the invalidation routine after the
      GuC was disabled, but missed that the GuC was unconditionally disabled
      when not used. This then overwrites the invalidate routine for the older
      chipsets, causing havoc and breaking resume as the most obvious victim.
      
      We place the guard inside i915_ggtt_disable_guc() to be backport
      friendly (the bug was introduced into v4.11) but it would be preferred
      to be in more control over when this was guard (i.e. do not try and
      teardown the data structures before we have enabled them). That should
      be true with the reorganisation of the guc loaders.
      Reported-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Fixes: 7c3f86b6 ("drm/i915: Invalidate the guc ggtt TLB upon insertion")
      Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
      Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
      Cc: Oscar Mateo <oscar.mateo@intel.com>
      Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
      Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
      Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
      Cc: <stable@vger.kernel.org> # v4.11+
      Link: http://patchwork.freedesktop.org/patch/msgid/20170531190514.3691-1-chris@chris-wilson.co.ukReviewed-by: default avatarMichel Thierry <michel.thierry@intel.com>
      (cherry picked from commit cb60606d)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      d90c9890
    • Maarten Lankhorst's avatar
      drm/i915: Always recompute watermarks when distrust_bios_wm is set, v2. · 4e3aed84
      Maarten Lankhorst authored
      On some systems there can be a race condition in which no crtc state is
      added to the first atomic commit. This results in all crtc's having a
      null DDB allocation, causing a FIFO underrun on any update until the
      first modeset.
      
      Changes since v1:
      - Do not take the connection_mutex, this is already done below.
      Reported-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
      Inspired-by: default avatarMahesh Kumar <mahesh1.kumar@intel.com>
      Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
      Fixes: 98d39494 ("drm/i915/gen9: Compute DDB allocation at atomic
      check time (v4)")
      Cc: <stable@vger.kernel.org> # v4.8+
      Cc: Mahesh Kumar <mahesh1.kumar@intel.com>
      Cc: Matt Roper <matthew.d.roper@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170531154236.27180-1-maarten.lankhorst@linux.intel.comReviewed-by: default avatarMahesh Kumar <mahesh1.kumar@intel.com>
      Reviewed-by: default avatarMatt Roper <matthew.d.roper@intel.com>
      
      (cherry picked from commit 367d73d2)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      4e3aed84
    • Imre Deak's avatar
      drm/i915: Prevent the system suspend complete optimization · 6ab92afc
      Imre Deak authored
      Since
      
      commit bac2a909
      Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
      Date:   Wed Jan 21 02:17:42 2015 +0100
      
          PCI / PM: Avoid resuming PCI devices during system suspend
      
      PCI devices will default to allowing the system suspend complete
      optimization where devices are not woken up during system suspend if
      they were already runtime suspended. This however breaks the i915/HDA
      drivers for two reasons:
      
      - The i915 driver has system suspend specific steps that it needs to
        run, that bring the device to a different state than its runtime
        suspended state.
      
      - The HDA driver's suspend handler requires power that it will request
        from the i915 driver's power domain handler. This in turn requires the
        i915 driver to runtime resume itself, but this won't be possible if the
        suspend complete optimization is in effect: in this case the i915
        runtime PM is disabled and trying to get an RPM reference returns
        -EACCESS.
      
      Solve this by requiring the PCI/PM core to resume the device during
      system suspend which in effect disables the suspend complete optimization.
      
      Regardless of the above commit the optimization stayed disabled for DRM
      devices until
      
      commit d14d2a84
      Author: Lukas Wunner <lukas@wunner.de>
      Date:   Wed Jun 8 12:49:29 2016 +0200
      
          drm: Remove dev_pm_ops from drm_class
      
      so this patch is in practice a fix for this commit. Another reason for
      the bug staying hidden for so long is that the optimization for a device
      is disabled if it's disabled for any of its children devices. i915 may
      have a backlight device as its child which doesn't support runtime PM
      and so doesn't allow the optimization either.  So if this backlight
      device got registered the bug stayed hidden.
      
      Credits to Marta, Tomi and David who enabled pstore logging,
      that caught one instance of this issue across a suspend/
      resume-to-ram and Ville who rememberd that the optimization was enabled
      for some devices at one point.
      
      The first WARN triggered by the problem:
      
      [ 6250.746445] WARNING: CPU: 2 PID: 17384 at drivers/gpu/drm/i915/intel_runtime_pm.c:2846 intel_runtime_pm_get+0x6b/0xd0 [i915]
      [ 6250.746448] pm_runtime_get_sync() failed: -13
      [ 6250.746451] Modules linked in: snd_hda_intel i915 vgem snd_hda_codec_hdmi x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul
      snd_hda_codec_realtek snd_hda_codec_generic ghash_clmulni_intel e1000e snd_hda_codec snd_hwdep snd_hda_core ptp mei_me pps_core snd_pcm lpc_ich mei prime_
      numbers i2c_hid i2c_designware_platform i2c_designware_core [last unloaded: i915]
      [ 6250.746512] CPU: 2 PID: 17384 Comm: kworker/u8:0 Tainted: G     U  W       4.11.0-rc5-CI-CI_DRM_334+ #1
      [ 6250.746515] Hardware name:                  /NUC5i5RYB, BIOS RYBDWi35.86A.0362.2017.0118.0940 01/18/2017
      [ 6250.746521] Workqueue: events_unbound async_run_entry_fn
      [ 6250.746525] Call Trace:
      [ 6250.746530]  dump_stack+0x67/0x92
      [ 6250.746536]  __warn+0xc6/0xe0
      [ 6250.746542]  ? pci_restore_standard_config+0x40/0x40
      [ 6250.746546]  warn_slowpath_fmt+0x46/0x50
      [ 6250.746553]  ? __pm_runtime_resume+0x56/0x80
      [ 6250.746584]  intel_runtime_pm_get+0x6b/0xd0 [i915]
      [ 6250.746610]  intel_display_power_get+0x1b/0x40 [i915]
      [ 6250.746646]  i915_audio_component_get_power+0x15/0x20 [i915]
      [ 6250.746654]  snd_hdac_display_power+0xc8/0x110 [snd_hda_core]
      [ 6250.746661]  azx_runtime_resume+0x218/0x280 [snd_hda_intel]
      [ 6250.746667]  pci_pm_runtime_resume+0x76/0xa0
      [ 6250.746672]  __rpm_callback+0xb4/0x1f0
      [ 6250.746677]  ? pci_restore_standard_config+0x40/0x40
      [ 6250.746682]  rpm_callback+0x1f/0x80
      [ 6250.746686]  ? pci_restore_standard_config+0x40/0x40
      [ 6250.746690]  rpm_resume+0x4ba/0x740
      [ 6250.746698]  __pm_runtime_resume+0x49/0x80
      [ 6250.746703]  pci_pm_suspend+0x57/0x140
      [ 6250.746709]  dpm_run_callback+0x6f/0x330
      [ 6250.746713]  ? pci_pm_freeze+0xe0/0xe0
      [ 6250.746718]  __device_suspend+0xf9/0x370
      [ 6250.746724]  ? dpm_watchdog_set+0x60/0x60
      [ 6250.746730]  async_suspend+0x1a/0x90
      [ 6250.746735]  async_run_entry_fn+0x34/0x160
      [ 6250.746741]  process_one_work+0x1f2/0x6d0
      [ 6250.746749]  worker_thread+0x49/0x4a0
      [ 6250.746755]  kthread+0x107/0x140
      [ 6250.746759]  ? process_one_work+0x6d0/0x6d0
      [ 6250.746763]  ? kthread_create_on_node+0x40/0x40
      [ 6250.746768]  ret_from_fork+0x2e/0x40
      [ 6250.746778] ---[ end trace 102a62fd2160f5e6 ]---
      
      v2:
      - Use the new pci_dev->needs_resume flag, to avoid any overhead during
        the ->pm_prepare hook. (Rafael)
      
      v3:
      - Update commit message to reference the actual regressing commit.
        (Lukas)
      
      v4:
      - Rebase on v4 of patch 1/2.
      
      Fixes: d14d2a84 ("drm: Remove dev_pm_ops from drm_class")
      References: https://bugs.freedesktop.org/show_bug.cgi?id=100378
      References: https://bugs.freedesktop.org/show_bug.cgi?id=100770
      Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
      Cc: Marta Lofstedt <marta.lofstedt@intel.com>
      Cc: David Weinehall <david.weinehall@linux.intel.com>
      Cc: Tomi Sarvela <tomi.p.sarvela@intel.com>
      Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
      Cc: Mika Kuoppala <mika.kuoppala@intel.com>
      Cc: Chris Wilson <chris@chris-wilson.co.uk>
      Cc: Takashi Iwai <tiwai@suse.de>
      Cc: Bjorn Helgaas <bhelgaas@google.com>
      Cc: Lukas Wunner <lukas@wunner.de>
      Cc: linux-pci@vger.kernel.org
      Cc: <stable@vger.kernel.org> # v4.10.x: 4d071c32 - PCI/PM: Add needs_resume flag
      Cc: <stable@vger.kernel.org> # v4.10.x
      Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
      Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Reported-and-tested-by: default avatarMarta Lofstedt <marta.lofstedt@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/1493726649-32094-2-git-send-email-imre.deak@intel.com
      (cherry picked from commit adfdf85d)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      6ab92afc
    • Nagaraju, Vathsala's avatar
      drm/i915/psr: disable psr2 for resolution greater than 32X20 · bd709898
      Nagaraju, Vathsala authored
      psr1 is also disabled for panel resolution  greater than 32X20.
      Added psr2 check to disable only for psr2 panels having resolution
      greater than 32X20.
      
      issue was introduced by
      commit-id : "acf45d11"
      commit message: "PSR2 is restricted to work with panel resolutions
      upto 3200x2000, move the check to intel_psr_match_conditions and fully
      block psr."
      
      v2: (Rodrigo)
         Add previous commit details which introduced the issue
      
      Fixes: acf45d11 ("drm/i915/psr: disable psr2 for resolution greater than 32X20")
      Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
      Cc: Jim Bride <jim.bride@linux.intel.com>
      Cc: Yaroslav Shabalin <yaroslav.shabalin@gmail.com>
      Reported-by: default avatarYaroslav Shabalin <yaroslav.shabalin@gmail.com>
      Reviewed-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      Signed-off-by: default avatarvathsala nagaraju <vathsala.nagaraju@intel.com>
      Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/49935bdff896ee3140bed471012b9f9110a863a4.1495729964.git.vathsala.nagaraju@intel.com
      (cherry picked from commit bef8c056)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      bd709898
    • Chris Wilson's avatar
      drm/i915: Hold a wakeref for probing the ring registers · d9533f19
      Chris Wilson authored
      Allow intel_engine_is_idle() to be called outside of the GT wakeref by
      acquiring the device runtime pm for ourselves. This allows the function
      to act as check after we assume the engine is idle and we release the GT
      wakeref held whilst we have requests. At the moment, we do not call it
      outside of an awake context but taking the wakeref as required makes it
      more convenient to use for quick debugging in future.
      
      [ 2613.401647] RPM wakelock ref not held during HW access
      [ 2613.401684] ------------[ cut here ]------------
      [ 2613.401720] WARNING: CPU: 5 PID: 7739 at drivers/gpu/drm/i915/intel_drv.h:1787 gen6_read32+0x21f/0x2b0 [i915]
      [ 2613.401731] Modules linked in: snd_hda_intel i915 vgem snd_hda_codec_hdmi x86_pkg_temp_thermal intel_powerclamp snd_hda_codec_realtek coretemp snd_hda_codec_generic crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec snd_hwdep snd_hda_core snd_pcm r8169 mii mei_me lpc_ich mei prime_numbers [last unloaded: i915]
      [ 2613.401823] CPU: 5 PID: 7739 Comm: drv_missed_irq Tainted: G     U          4.12.0-rc2-CI-CI_DRM_421+ #1
      [ 2613.401825] Hardware name: MSI MS-7924/Z97M-G43(MS-7924), BIOS V1.12 02/15/2016
      [ 2613.401840] task: ffff880409e3a740 task.stack: ffffc900084dc000
      [ 2613.401861] RIP: 0010:gen6_read32+0x21f/0x2b0 [i915]
      [ 2613.401863] RSP: 0018:ffffc900084dfce8 EFLAGS: 00010292
      [ 2613.401869] RAX: 000000000000002a RBX: ffff8804016a8000 RCX: 0000000000000006
      [ 2613.401871] RDX: 0000000000000006 RSI: ffffffff81cbf2d9 RDI: ffffffff81c9e3a7
      [ 2613.401874] RBP: ffffc900084dfd18 R08: ffff880409e3afc8 R09: 0000000000000000
      [ 2613.401877] R10: 000000008a1c483f R11: 0000000000000000 R12: 000000000000209c
      [ 2613.401879] R13: 0000000000000001 R14: ffff8804016a8000 R15: ffff8804016ac150
      [ 2613.401882] FS:  00007f39ef3dd8c0(0000) GS:ffff88041fb40000(0000) knlGS:0000000000000000
      [ 2613.401885] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [ 2613.401887] CR2: 00000000023717c8 CR3: 00000002e7b34000 CR4: 00000000001406e0
      [ 2613.401889] Call Trace:
      [ 2613.401912]  intel_engine_is_idle+0x76/0x90 [i915]
      [ 2613.401931]  i915_gem_wait_for_idle+0xe6/0x1e0 [i915]
      [ 2613.401951]  fault_irq_set+0x40/0x90 [i915]
      [ 2613.401970]  i915_ring_test_irq_set+0x42/0x50 [i915]
      [ 2613.401976]  simple_attr_write+0xc7/0xe0
      [ 2613.401981]  full_proxy_write+0x4f/0x70
      [ 2613.401987]  __vfs_write+0x23/0x120
      [ 2613.401992]  ? rcu_read_lock_sched_held+0x75/0x80
      [ 2613.401996]  ? rcu_sync_lockdep_assert+0x2a/0x50
      [ 2613.401999]  ? __sb_start_write+0xfa/0x1f0
      [ 2613.402004]  vfs_write+0xc5/0x1d0
      [ 2613.402008]  ? trace_hardirqs_on_caller+0xe7/0x1c0
      [ 2613.402013]  SyS_write+0x44/0xb0
      [ 2613.402020]  entry_SYSCALL_64_fastpath+0x1c/0xb1
      [ 2613.402022] RIP: 0033:0x7f39eded6670
      [ 2613.402025] RSP: 002b:00007fffdcdcb1a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
      [ 2613.402030] RAX: ffffffffffffffda RBX: ffffffff81470203 RCX: 00007f39eded6670
      [ 2613.402033] RDX: 0000000000000001 RSI: 000000000041bc33 RDI: 0000000000000006
      [ 2613.402036] RBP: ffffc900084dff88 R08: 00007f39ef3dd8c0 R09: 0000000000000001
      [ 2613.402038] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000041bc33
      [ 2613.402041] R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
      [ 2613.402046]  ? __this_cpu_preempt_check+0x13/0x20
      [ 2613.402052] Code: 01 9b fa e0 0f ff e9 28 fe ff ff 80 3d 6a dd 0e 00 00 0f 85 29 fe ff ff 48 c7 c7 48 19 29 a0 c6 05 56 dd 0e 00 01 e8 da 9a fa e0 <0f> ff e9 0f fe ff ff b9 01 00 00 00 ba 01 00 00 00 44 89 e6 48
      [ 2613.402199] ---[ end trace 31f0cfa93ab632bf ]---
      
      Fixes: 5400367a ("drm/i915: Ensure the engine is idle before manually changing HWS")
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Cc: Mika Kuoppala <mika.kuoppala@intel.com>
      Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170530121334.17364-2-chris@chris-wilson.co.ukReviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
      (cherry picked from commit a091d4ee)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      d9533f19
    • Chris Wilson's avatar
      drm/i915: Short-circuit i915_gem_wait_for_idle() if already idle · e0da1963
      Chris Wilson authored
      If the device is asleep (no GT wakeref), we know the GPU is already idle.
      If we add an early return, we can avoid touching registers and checking
      hw state outside of the assumed GT wakelock. This prevents causing such
      errors whilst debugging:
      
      [ 2613.401647] RPM wakelock ref not held during HW access
      [ 2613.401684] ------------[ cut here ]------------
      [ 2613.401720] WARNING: CPU: 5 PID: 7739 at drivers/gpu/drm/i915/intel_drv.h:1787 gen6_read32+0x21f/0x2b0 [i915]
      [ 2613.401731] Modules linked in: snd_hda_intel i915 vgem snd_hda_codec_hdmi x86_pkg_temp_thermal intel_powerclamp snd_hda_codec_realtek coretemp snd_hda_codec_generic crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec snd_hwdep snd_hda_core snd_pcm r8169 mii mei_me lpc_ich mei prime_numbers [last unloaded: i915]
      [ 2613.401823] CPU: 5 PID: 7739 Comm: drv_missed_irq Tainted: G     U          4.12.0-rc2-CI-CI_DRM_421+ #1
      [ 2613.401825] Hardware name: MSI MS-7924/Z97M-G43(MS-7924), BIOS V1.12 02/15/2016
      [ 2613.401840] task: ffff880409e3a740 task.stack: ffffc900084dc000
      [ 2613.401861] RIP: 0010:gen6_read32+0x21f/0x2b0 [i915]
      [ 2613.401863] RSP: 0018:ffffc900084dfce8 EFLAGS: 00010292
      [ 2613.401869] RAX: 000000000000002a RBX: ffff8804016a8000 RCX: 0000000000000006
      [ 2613.401871] RDX: 0000000000000006 RSI: ffffffff81cbf2d9 RDI: ffffffff81c9e3a7
      [ 2613.401874] RBP: ffffc900084dfd18 R08: ffff880409e3afc8 R09: 0000000000000000
      [ 2613.401877] R10: 000000008a1c483f R11: 0000000000000000 R12: 000000000000209c
      [ 2613.401879] R13: 0000000000000001 R14: ffff8804016a8000 R15: ffff8804016ac150
      [ 2613.401882] FS:  00007f39ef3dd8c0(0000) GS:ffff88041fb40000(0000) knlGS:0000000000000000
      [ 2613.401885] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [ 2613.401887] CR2: 00000000023717c8 CR3: 00000002e7b34000 CR4: 00000000001406e0
      [ 2613.401889] Call Trace:
      [ 2613.401912]  intel_engine_is_idle+0x76/0x90 [i915]
      [ 2613.401931]  i915_gem_wait_for_idle+0xe6/0x1e0 [i915]
      [ 2613.401951]  fault_irq_set+0x40/0x90 [i915]
      [ 2613.401970]  i915_ring_test_irq_set+0x42/0x50 [i915]
      [ 2613.401976]  simple_attr_write+0xc7/0xe0
      [ 2613.401981]  full_proxy_write+0x4f/0x70
      [ 2613.401987]  __vfs_write+0x23/0x120
      [ 2613.401992]  ? rcu_read_lock_sched_held+0x75/0x80
      [ 2613.401996]  ? rcu_sync_lockdep_assert+0x2a/0x50
      [ 2613.401999]  ? __sb_start_write+0xfa/0x1f0
      [ 2613.402004]  vfs_write+0xc5/0x1d0
      [ 2613.402008]  ? trace_hardirqs_on_caller+0xe7/0x1c0
      [ 2613.402013]  SyS_write+0x44/0xb0
      [ 2613.402020]  entry_SYSCALL_64_fastpath+0x1c/0xb1
      [ 2613.402022] RIP: 0033:0x7f39eded6670
      [ 2613.402025] RSP: 002b:00007fffdcdcb1a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
      [ 2613.402030] RAX: ffffffffffffffda RBX: ffffffff81470203 RCX: 00007f39eded6670
      [ 2613.402033] RDX: 0000000000000001 RSI: 000000000041bc33 RDI: 0000000000000006
      [ 2613.402036] RBP: ffffc900084dff88 R08: 00007f39ef3dd8c0 R09: 0000000000000001
      [ 2613.402038] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000041bc33
      [ 2613.402041] R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
      [ 2613.402046]  ? __this_cpu_preempt_check+0x13/0x20
      [ 2613.402052] Code: 01 9b fa e0 0f ff e9 28 fe ff ff 80 3d 6a dd 0e 00 00 0f 85 29 fe ff ff 48 c7 c7 48 19 29 a0 c6 05 56 dd 0e 00 01 e8 da 9a fa e0 <0f> ff e9 0f fe ff ff b9 01 00 00 00 ba 01 00 00 00 44 89 e6 48
      [ 2613.402199] ---[ end trace 31f0cfa93ab632bf ]---
      
      Fixes: 25112b64 ("drm/i915: Wait for all engines to be idle as part of i915_gem_wait_for_idle()")
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170530121334.17364-1-chris@chris-wilson.co.ukReviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
      (cherry picked from commit 863e9fde)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      e0da1963
    • Kai Chen's avatar
      drm/i915: Disable decoupled MMIO · 4c4c5655
      Kai Chen authored
      The decoupled MMIO feature doesn't work as intended by HW team. Enabling
      it with forcewake will only make debugging efforts more difficult, so
      let's disable it.
      
      Fixes: 85ee17eb ("drm/i915/bxt: Broxton decoupled MMIO")
      Cc: Zhe Wang <zhe1.wang@intel.com>
      Cc: Praveen Paneri <praveen.paneri@intel.com>
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Cc: Daniel Vetter <daniel.vetter@intel.com>
      Cc: Jani Nikula <jani.nikula@linux.intel.com>
      Cc: intel-gfx@lists.freedesktop.org
      Cc: <stable@vger.kernel.org> # v4.10+
      Signed-off-by: default avatarKai Chen <kai.chen@intel.com>
      Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170523215812.18328-2-kai.chen@intel.com
      (cherry picked from commit 0051c10a)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      4c4c5655
    • Michal Wajdeczko's avatar
      drm/i915/guc: Remove stale comment for q_fail · 4ca9a582
      Michal Wajdeczko authored
      This member was dropped long time ago.
      
      Fixes: 774439e1 ("drm/i915/guc: re-optimise i915_guc_client layout")
      Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Link: http://patchwork.freedesktop.org/patch/msgid/20170518113104.54400-1-michal.wajdeczko@intel.comReviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      (cherry picked from commit 4afc67be)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      4ca9a582
    • Jon Bloomfield's avatar
      drm/i915: Serialize GTT/Aperture accesses on BXT · d86b18a0
      Jon Bloomfield authored
      BXT has a H/W issue with IOMMU which can lead to system hangs when
      Aperture accesses are queued within the GAM behind GTT Accesses.
      
      This patch avoids the condition by wrapping all GTT updates in stop_machine
      and using a flushing read prior to restarting the machine.
      
      The stop_machine guarantees no new Aperture accesses can begin while
      the PTE writes are being emmitted. The flushing read ensures that
      any following Aperture accesses cannot begin until the PTE writes
      have been cleared out of the GAM's fifo.
      
      Only FOLLOWING Aperture accesses need to be separated from in flight
      PTE updates. PTE Writes may follow tightly behind already in flight
      Aperture accesses, so no flushing read is required at the start of
      a PTE update sequence.
      
      This issue was reproduced by running
      	igt/gem_readwrite and
      	igt/gem_render_copy
      simultaneously from different processes, each in a tight loop,
      with INTEL_IOMMU enabled.
      
      This patch was originally published as:
      	drm/i915: Serialize GTT Updates on BXT
      
      [Note: This will cause a performance penalty for some use cases, but
      avoiding hangs trumps performance hits. This may need to be worked
      around in Mesa to recover the lost performance.]
      
      v2: Move bxt/iommu detection into static function
          Remove #ifdef CONFIG_INTEL_IOMMU protection
          Make function names more reflective of purpose
          Move flushing read into static function
      
      v3: Tidy up for checkpatch.pl
      
      Testcase: igt/gem_concurrent_blit
      Signed-off-by: default avatarJon Bloomfield <jon.bloomfield@intel.com>
      Cc: John Harrison <john.C.Harrison@intel.com>
      Cc: Chris Wilson <chris@chris-wilson.co.uk>
      Cc: Daniel Vetter <daniel.vetter@intel.com>
      Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
      Cc: stable@vger.kernel.org
      Link: http://patchwork.freedesktop.org/patch/msgid/1495641251-30022-1-git-send-email-jon.bloomfield@intel.comReviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
      Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
      (cherry picked from commit 0ef34ad6)
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      d86b18a0
  5. 04 Jun, 2017 9 commits
    • Linus Torvalds's avatar
      Linux 4.12-rc4 · 3c2993b8
      Linus Torvalds authored
      3c2993b8
    • Richard Narron's avatar
      fs/ufs: Set UFS default maximum bytes per file · 239e250e
      Richard Narron authored
      This fixes a problem with reading files larger than 2GB from a UFS-2
      file system:
      
          https://bugzilla.kernel.org/show_bug.cgi?id=195721
      
      The incorrect UFS s_maxsize limit became a problem as of commit
      c2a9737f ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
      which started using s_maxbytes to avoid a page index overflow in
      do_generic_file_read().
      
      That caused files to be truncated on UFS-2 file systems because the
      default maximum file size is 2GB (MAX_NON_LFS) and UFS didn't update it.
      
      Here I simply increase the default to a common value used by other file
      systems.
      Signed-off-by: default avatarRichard Narron <comet.berkeley@gmail.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Will B <will.brokenbourgh2877@gmail.com>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Cc: <stable@vger.kernel.org> # v4.9 and backports of c2a9737fSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      239e250e
    • Linus Torvalds's avatar
      Merge tag 'nfs-for-4.12-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs · 125f42b0
      Linus Torvalds authored
      Pull NFS client bugfixes from Trond Myklebust:
       "Bugfixes include:
      
         - Fix a typo in commit e0926934 ("NFS append COMMIT after
           synchronous COPY") that breaks copy offload
      
         - Fix the connect error propagation in xs_tcp_setup_socket()
      
         - Fix a lock leak in nfs40_walk_client_list
      
         - Verify that pNFS requests lie within the offset range of the layout
           segment"
      
      * tag 'nfs-for-4.12-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
        nfs: Mark unnecessarily extern functions as static
        SUNRPC: ensure correct error is reported by xs_tcp_setup_socket()
        NFSv4.0: Fix a lock leak in nfs40_walk_client_list
        pnfs: Fix the check for requests in range of layout segment
        xprtrdma: Delete an error message for a failed memory allocation in xprt_rdma_bc_setup()
        pNFS/flexfiles: missing error code in ff_layout_alloc_lseg()
        NFS fix COMMIT after COPY
      125f42b0
    • Linus Torvalds's avatar
      Merge tag 'tty-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty · 3c06e6cb
      Linus Torvalds authored
      Pull tty fix from Greg KH:
       "Here is a single tty core fix for 4.12-rc4. It reverts a patch that a
        lot of people reported as causing lockdep and other warnings.
      
        Right after I reverted this in my tree, it seems like another
        "correct" fix might have shown up, but it's too late in the release
        cycle to be messing with tty core locking, so let's just revert this
        for now to go back how things always have been and try it again for
        4.13.
      
        This has not been in linux-next as I only reverted it a few hours ago"
      
      * tag 'tty-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
        Revert "tty: fix port buffer locking"
      3c06e6cb
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input · e00811b4
      Linus Torvalds authored
      Pull input subsystem fixes from Dmitry Torokhov:
      
       - a couple of regression fixes in synaptics and axp20x-pek drivers
      
       - try to ease transition from PS/2 to RMI for Synaptics touchpad users
         by ensuring we do not try to activate RMI mode when RMI SMBus support
         is not enabled, and nag users a bit to enable it
      
       - plus a couple of other changes that seemed worthwhile for this
         release
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
        Input: axp20x-pek - switch to acpi_dev_present and check for ACPI0011 too
        Input: axp20x-pek - only check for "INTCFD9" ACPI device on Cherry Trail
        Input: tm2-touchkey - use LEN_ON as boolean value instead of LED_FULL
        Input: synaptics - tell users to report when they should be using rmi-smbus
        Input: synaptics - warn the users when there is a better mode
        Input: synaptics - keep PS/2 around when RMI4_SMB is not enabled
        Input: synaptics - clear device info before filling in
        Input: silead - disable interrupt during suspend
      e00811b4
    • Linus Torvalds's avatar
      Merge tag 'rtc-4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux · 9f03b2c7
      Linus Torvalds authored
      Pull RTC fixlet from Alexandre Belloni:
       "A single patch, not really a fix but I don't think there is any reason
        to delay it.
      
        Change the mailing list address"
      
      * tag 'rtc-4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
        MAINTAINERS: update RTC mailing list
      9f03b2c7
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 1f915b7f
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "This is nine fixes, seven of which are for the qedi driver (new as of
        4.10) the other two are a use after free in the cxgbi drivers and a
        potential NULL dereference in the rdac device handler"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: libcxgbi: fix skb use after free
        scsi: qedi: Fix endpoint NULL panic during recovery.
        scsi: qedi: set max_fin_rt default value
        scsi: qedi: Set firmware tcp msl timer value.
        scsi: qedi: Fix endpoint NULL panic in qedi_set_path.
        scsi: qedi: Set dma_boundary to 0xfff.
        scsi: qedi: Correctly set firmware max supported BDs.
        scsi: qedi: Fix bad pte call trace when iscsiuio is stopped.
        scsi: scsi_dh_rdac: Use ctlr directly in rdac_failover_get()
      1f915b7f
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma · 55cbdaf6
      Linus Torvalds authored
      Pull rdma fixes from Doug Ledford:
       "For the most part this is just a minor -rc cycle for the rdma
        subsystem. Even given that this is all of the -rc patches since the
        merge window closed, it's still only about 25 patches:
      
         - Multiple i40iw, nes, iw_cxgb4, hfi1, qib, mlx4, mlx5 fixes
      
         - A few upper layer protocol fixes (IPoIB, iSER, SRP)
      
         - A modest number of core fixes"
      
      * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (26 commits)
        RDMA/SA: Fix kernel panic in CMA request handler flow
        RDMA/umem: Fix missing mmap_sem in get umem ODP call
        RDMA/core: not to set page dirty bit if it's already set.
        RDMA/uverbs: Declare local function static and add brackets to sizeof
        RDMA/netlink: Reduce exposure of RDMA netlink functions
        RDMA/srp: Fix NULL deref at srp_destroy_qp()
        RDMA/IPoIB: Limit the ipoib_dev_uninit_default scope
        RDMA/IPoIB: Replace netdev_priv with ipoib_priv for ipoib_get_link_ksettings
        RDMA/qedr: add null check before pointer dereference
        RDMA/mlx5: set UMR wqe fence according to HCA cap
        net/mlx5: Define interface bits for fencing UMR wqe
        RDMA/mlx4: Fix MAD tunneling when SRIOV is enabled
        RDMA/qib,hfi1: Fix MR reference count leak on write with immediate
        RDMA/hfi1: Defer setting VL15 credits to link-up interrupt
        RDMA/hfi1: change PCI bar addr assignments to Linux API functions
        RDMA/hfi1: fix array termination by appending NULL to attr array
        RDMA/iw_cxgb4: fix the calculation of ipv6 header size
        RDMA/iw_cxgb4: calculate t4_eq_status_entries properly
        RDMA/iw_cxgb4: Avoid touch after free error in ARP failure handlers
        RDMA/nes: ACK MPA Reply frame
        ...
      55cbdaf6
    • Greg Kroah-Hartman's avatar
      Revert "tty: fix port buffer locking" · fc098af1
      Greg Kroah-Hartman authored
      This reverts commit 925bb1ce.
      
      It causes lots of warnings and problems so for now, let's just revert
      it.
      
      Reported-by: <valdis.kletnieks@vt.edu>
      Reported-by: default avatarRussell King <linux@armlinux.org.uk>
      Reported-by: default avatarSergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
      Reported-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
      Reported-by: default avatarJiri Slaby <jslaby@suse.cz>
      Reported-by: default avatarAndrey Konovalov <andreyknvl@google.com>
      Acked-by: default avatarVegard Nossum <vegard.nossum@oracle.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      fc098af1
  6. 03 Jun, 2017 8 commits
  7. 02 Jun, 2017 5 commits
    • Linus Torvalds's avatar
      Merge tag 'acpi-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 104c08ba
      Linus Torvalds authored
      Pull ACPI fixes from Rafael Wysocki:
       "These revert one more problematic commit related to the ACPI-based
        handling of laptop lids and make some unuseful error messages coming
        from ACPICA go away.
      
        Specifics:
      
         - Revert one more commit related to the ACPI-based handling of laptop
           lids that changed the default behavior on laptops that booted with
           closed lids and introduced a regression there (Benjamin Tissoires).
      
         - Add a missing acpi_put_table() to the code implementing the
           /sys/firmware/acpi/tables interface to prevent a counter in the
           ACPICA core from overflowing (Dan Williams).
      
         - Drop error messages printed by ACPICA on acpi_get_table() reference
           counting mismatches as they need not indicate real errors at this
           point (Lv Zheng)"
      
      * tag 'acpi-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
        ACPICA: Tables: Fix regression introduced by a too early mechanism enabling
        Revert "ACPI / button: Change default behavior to lid_init_state=open"
        ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service
      104c08ba
    • Linus Torvalds's avatar
      Merge tag 'pm-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 89af529a
      Linus Torvalds authored
      Pull power management fixes from Rafael Wysocki:
       "These fix two bugs in error code paths in the cpufreq core and in the
        kirkwood-cpufreq driver.
      
        Specifics:
      
         - Make cpufreq_register_driver() return an error if the ->init()
           calls fail for all CPUs to prevent non-functional drivers from
           hanging around for no reason (David Arcari).
      
         - Make kirkwood-cpufreq check the return value of
           clk_prepare_enable() (which may fail) as appropriate (Arvind
           Yadav)"
      
      * tag 'pm-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
        cpufreq: kirkwood-cpufreq:- Handle return value of clk_prepare_enable()
        cpufreq: cpufreq_register_driver() should return -ENODEV if init fails
      89af529a
    • Linus Torvalds's avatar
      Merge tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random · 5a4829b5
      Linus Torvalds authored
      Pull /dev/random bug fix from Ted Ts'o:
       "Fix a race on architectures with prioritized interrupts (such as m68k)
        which can causes crashes in drivers/char/random.c:get_reg()"
      
      * tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
        fix race in drivers/char/random.c:get_reg()
      5a4829b5
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · f2197649
      Linus Torvalds authored
      Merge misc fixes from Andrew Morton:
       "15 fixes"
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>:
        scripts/gdb: make lx-dmesg command work (reliably)
        mm: consider memblock reservations for deferred memory initialization sizing
        mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified
        mlock: fix mlock count can not decrease in race condition
        mm/migrate: fix refcount handling when !hugepage_migration_supported()
        dax: fix race between colliding PMD & PTE entries
        mm: avoid spurious 'bad pmd' warning messages
        mm/page_alloc.c: make sure OOM victim can try allocations with no watermarks once
        pcmcia: remove left-over %Z format
        slub/memcg: cure the brainless abuse of sysfs attributes
        initramfs: fix disabling of initramfs (and its compression)
        mm: clarify why we want kmalloc before falling backto vmallock
        frv: declare jiffies to be located in the .data section
        include/linux/gfp.h: fix ___GFP_NOLOCKDEP value
        ksm: prevent crash after write_protect_page fails
      f2197649
    • André Draszik's avatar
      scripts/gdb: make lx-dmesg command work (reliably) · d6c97087
      André Draszik authored
      lx-dmesg needs access to the log_buf symbol from printk.c.
      Unfortunately, the symbol log_buf also exists in BPF's verifier.c and
      hence gdb can pick one or the other.  If it happens to pick BPF's
      log_buf, lx-dmesg doesn't work:
      
        (gdb) lx-dmesg
        Python Exception <class 'gdb.MemoryError'> Cannot access memory at address 0x0:
        Error occurred in Python command: Cannot access memory at address 0x0
        (gdb) p log_buf
        $15 = 0x0
      
      Luckily, GDB has a way to deal with this, see
        https://sourceware.org/gdb/onlinedocs/gdb/Symbols.html
      
        (gdb) info variables ^log_buf$
        All variables matching regular expression "^log_buf$":
      
        File <linux.git>/kernel/bpf/verifier.c:
        static char *log_buf;
      
        File <linux.git>/kernel/printk/printk.c:
        static char *log_buf;
        (gdb) p 'verifier.c'::log_buf
        $1 = 0x0
        (gdb) p 'printk.c'::log_buf
        $2 = 0x811a6aa0 <__log_buf> ""
        (gdb) p &log_buf
        $3 = (char **) 0x8120fe40 <log_buf>
        (gdb) p &'verifier.c'::log_buf
        $4 = (char **) 0x8120fe40 <log_buf>
        (gdb) p &'printk.c'::log_buf
        $5 = (char **) 0x8048b7d0 <log_buf>
      
      By being explicit about the location of the symbol, we can make lx-dmesg
      work again.  While at it, do the same for the other symbols we need from
      printk.c
      
      Link: http://lkml.kernel.org/r/20170526112222.3414-1-git@andred.netSigned-off-by: default avatarAndré Draszik <git@andred.net>
      Tested-by: default avatarKieran Bingham <kieran@bingham.xyz>
      Acked-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d6c97087