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  1. 25 Jan, 2013 3 commits
  3. 22 Jan, 2013 2 commits
  5. 21 Jan, 2013 7 commits
  7. 20 Jan, 2013 2 commits
  9. 19 Jan, 2013 3 commits
    • Joe Millenbach's avatar
      tty: Added a CONFIG_TTY option to allow removal of TTY · 4f73bc4d
      Joe Millenbach authored 
      The option allows you to remove TTY and compile without errors. This
saves space on systems that won't support TTY interfaces anyway.
bloat-o-meter output is below.

The bulk of this patch consists of Kconfig changes adding "depends on
TTY" to various serial devices and similar drivers that require the TTY
layer.  Ideally, these dependencies would occur on a common intermediate
symbol such as SERIO, but most drivers "select SERIO" rather than
"depends on SERIO", and "select" does not respect dependencies.

bloat-o-meter output comparing our previous minimal to new minimal by
removing TTY.  The list is filtered to not show removed entries with awk
'$3 != "-"' as the list was very long.

add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350)
function                                     old     new   delta
chr_dev_init                                 166     170      +4
allow_signal                                  80      82      +2
static.__warned                              143     142      -1
disallow_signal                               63      62      -1
__set_special_pids                            95      94      -1
unregister_console                           126     121      -5
start_kernel                                 546     541      -5
register_console                             593     588      -5
copy_from_user                                45      40      -5
sys_setsid                                   128     120      -8
sys_vhangup                                   32      19     -13
do_exit                                     1543    1526     -17
bitmap_zero                                   60      40     -20
arch_local_irq_save                          137     117     -20
release_task                                 674     652     -22
static.spin_unlock_irqrestore                308     260     -48
Signed-off-by: default avatarJoe Millenbach <jmillenbach@gmail.com>
Reviewed-by: default avatarJamey Sharp <jamey@minilop.net>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4f73bc4d
    • Ilya Zykov's avatar
      tty: Add driver unthrottle in ioctl(...,TCFLSH,..). · a1bf9584
      Ilya Zykov authored 
      Regression 'tty: fix "IRQ45: nobody cared"'
Regression commit 7b292b4b

  Function reset_buffer_flags() also invoked during the ioctl(...,TCFLSH,..).
At the time of request we can have full buffers and throttled driver too.
If we don't unthrottle driver, we can get forever throttled driver, because,
after request, we will have empty buffers and throttled driver and
there is no place to unthrottle driver.
It simple reproduce with "pty" pair then one side sleep on tty->write_wait,
and other side do ioctl(...,TCFLSH,..). Then there is no place to do writers wake up.
Signed-off-by: default avatarIlya Zykov <ilya@ilyx.ru>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a1bf9584
    • Thierry Reding's avatar
      serial: lpc32xx: Fix fallout from tty_port conversion · 33aeb9da
      Thierry Reding authored 
      A duplicate definition of the port variable was introduced in the
interrupt handler, which causes the build to break. The fix is to
rename the variable to tport, which is already properly used in
subsequent code.
Signed-off-by: default avatarThierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      33aeb9da
  11. 18 Jan, 2013 15 commits
  13. 16 Jan, 2013 8 commits
    • Greg Kroah-Hartman's avatar
      Staging: sb105x: mark it BROKEN · e27a7d79
      Greg Kroah-Hartman authored 
      It isn't using the port logic, and breaks the build at the moment, so
mark it BROKEN.

Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e27a7d79
    • Jiri Slaby's avatar
      TTY: mn10300-serial, fix build breakage · 59c5f924
      Jiri Slaby authored 
      By the recent `switch flipping' patches we introduced a build failure
in the driver:
mn10300-serial.c:527:19: error: 'port' redeclared as different kind of symbol

I did not notice because I did not even find a compiler for that new
architecture. Hopefully everything is all right now as I cannot test
it.
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      59c5f924
    • Jiri Slaby's avatar
      TTY: ip22zilog, fix tty_flip_buffer_push call · 2894500d
      Jiri Slaby authored 
      This one was omitted by the "TTY: switch tty_flip_buffer_push" patch
because I did not compile-test mips driver. Now I do.
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2894500d
    • Heikki Krogerus's avatar
      serial: 8250_dw: Set maxburst size · f5836a55
      Heikki Krogerus authored 
      The default burst is often 1 byte which is not very optimal.
The ideal burst size when using 16550A type port would be
1/2 of fifosize, but this does not work with all Designware
implementations. Setting it to 1/4 fifosize.
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f5836a55
    • Heikki Krogerus's avatar
      serial: 8250_dw: Use ifdef with ACPI · 053fac36
      Heikki Krogerus authored 
      There are no stubs for ACPI functions so the driver needs to
have this ifdef or it will not compile without ACPI.
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      053fac36
    • Heikki Krogerus's avatar
      serial: 8250_dma: TX optimisation · a3b0397f
      Heikki Krogerus authored 
      Remove one useless wakeup, and do not use DMA with zero byte
transfers.
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a3b0397f
    • Heikki Krogerus's avatar
      serial: 8250_dma: Switch to using tty_port · 6f3fe3b1
      Heikki Krogerus authored 
      The tty buffer functions are converted to using tty_port
structure instead of struct tty, so we must do the same.
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6f3fe3b1
    • Sebastian Andrzej Siewior's avatar
      tty: don't deadlock while flushing workqueue · 852e4a81
      Sebastian Andrzej Siewior authored 
      Since commit 89c8d91e ("tty: localise the lock") I see a dead lock
in one of my dummy_hcd + g_nokia test cases. The first run was usually
okay, the second often resulted in a splat by lockdep and the third was
usually a dead lock.
Lockdep complained about tty->hangup_work and tty->legacy_mutex taken
both ways:
| ======================================================
| [ INFO: possible circular locking dependency detected ]
| 3.7.0-rc6+ #204 Not tainted
| -------------------------------------------------------
| kworker/2:1/35 is trying to acquire lock:
|  (&tty->legacy_mutex){+.+.+.}, at: [<c14051e6>] tty_lock_nested+0x36/0x80
|
| but task is already holding lock:
|  ((&tty->hangup_work)){+.+...}, at: [<c104f6e4>] process_one_work+0x124/0x5e0
|
| which lock already depends on the new lock.
|
| the existing dependency chain (in reverse order) is:
|
| -> #2 ((&tty->hangup_work)){+.+...}:
|        [<c107fe74>] lock_acquire+0x84/0x190
|        [<c104d82d>] flush_work+0x3d/0x240
|        [<c12e6986>] tty_ldisc_flush_works+0x16/0x30
|        [<c12e7861>] tty_ldisc_release+0x21/0x70
|        [<c12e0dfc>] tty_release+0x35c/0x470
|        [<c1105e28>] __fput+0xd8/0x270
|        [<c1105fcd>] ____fput+0xd/0x10
|        [<c1051dd9>] task_work_run+0xb9/0xf0
|        [<c1002a51>] do_notify_resume+0x51/0x80
|        [<c140550a>] work_notifysig+0x35/0x3b
|
| -> #1 (&tty->legacy_mutex/1){+.+...}:
|        [<c107fe74>] lock_acquire+0x84/0x190
|        [<c140276c>] mutex_lock_nested+0x6c/0x2f0
|        [<c14051e6>] tty_lock_nested+0x36/0x80
|        [<c1405279>] tty_lock_pair+0x29/0x70
|        [<c12e0bb8>] tty_release+0x118/0x470
|        [<c1105e28>] __fput+0xd8/0x270
|        [<c1105fcd>] ____fput+0xd/0x10
|        [<c1051dd9>] task_work_run+0xb9/0xf0
|        [<c1002a51>] do_notify_resume+0x51/0x80
|        [<c140550a>] work_notifysig+0x35/0x3b
|
| -> #0 (&tty->legacy_mutex){+.+.+.}:
|        [<c107f3c9>] __lock_acquire+0x1189/0x16a0
|        [<c107fe74>] lock_acquire+0x84/0x190
|        [<c140276c>] mutex_lock_nested+0x6c/0x2f0
|        [<c14051e6>] tty_lock_nested+0x36/0x80
|        [<c140523f>] tty_lock+0xf/0x20
|        [<c12df8e4>] __tty_hangup+0x54/0x410
|        [<c12dfcb2>] do_tty_hangup+0x12/0x20
|        [<c104f763>] process_one_work+0x1a3/0x5e0
|        [<c104fec9>] worker_thread+0x119/0x3a0
|        [<c1055084>] kthread+0x94/0xa0
|        [<c140ca37>] ret_from_kernel_thread+0x1b/0x28
|
|other info that might help us debug this:
|
|Chain exists of:
|  &tty->legacy_mutex --> &tty->legacy_mutex/1 --> (&tty->hangup_work)
|
| Possible unsafe locking scenario:
|
|       CPU0                    CPU1
|       ----                    ----
|  lock((&tty->hangup_work));
|                               lock(&tty->legacy_mutex/1);
|                               lock((&tty->hangup_work));
|  lock(&tty->legacy_mutex);
|
| *** DEADLOCK ***

Before the path mentioned tty_ldisc_release() look like this:

|	tty_ldisc_halt(tty);
|	tty_ldisc_flush_works(tty);
|	tty_lock();

As it can be seen, it first flushes the workqueue and then grabs the
tty_lock. Now we grab the lock first:

|	tty_lock_pair(tty, o_tty);
|	tty_ldisc_halt(tty);
|	tty_ldisc_flush_works(tty);

so lockdep's complaint seems valid.

The earlier version of this patch took the ldisc_mutex since the other
user of tty_ldisc_flush_works() (tty_set_ldisc()) did this.
Peter Hurley then said that it is should not be requried. Since it
wasn't done earlier, I dropped this part.
The code under tty_ldisc_kill() was executed earlier with the tty lock
taken so it is taken again.

I was able to reproduce the deadlock on v3.8-rc1, this patch fixes the
problem in my testcase. I didn't notice any problems so far.

Cc: Alan Cox <alan@linux.intel.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      852e4a81
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