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  1. Jun 18, 2013
  3. Jun 17, 2013
    • Peter Hurley's avatar
      tty: Reset itty for other pty · 64e377dc
      Peter Hurley authored 
      

Commit 19ffd68f
('pty: Remove redundant itty reset') introduced a regression
whereby the other pty's linkage is not cleared on teardown.
This triggers a false positive diagnostic in testing.

Properly reset the itty linkage.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org> # 3.10
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      64e377dc
    • Peter Hurley's avatar
      n_tty: Buffer work should not reschedule itself · 7879a9f9
      Peter Hurley authored 
      

Although the driver-side input path must update the available
buffer space, it should not reschedule itself. If space is still
available and the flip buffers are not empty, flush_to_ldisc()
will loop again.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7879a9f9
    • Peter Hurley's avatar
      n_tty: Fix unsafe update of available buffer space · b8483052
      Peter Hurley authored 
      

receive_room is used to control the amount of data the flip
buffer work can push to the read buffer. This update is unsafe:

  CPU 0                        |  CPU 1
                               |
                               | n_tty_read()
                               |   n_tty_set_room()
                               |     left = <calc of space>
n_tty_receive_buf()            |
  <push data to buffer>        |
  n_tty_set_room()             |
    left = <calc of space>     |
    tty->receive_room = left   |
                               |     tty->receive_room = left

receive_room is now updated with a stale calculation of the
available buffer space, and the subsequent work loop will likely
overwrite unread data in the input buffer.

Update receive_room atomically with the calculation of the
available buffer space.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b8483052
    • Peter Hurley's avatar
      n_tty: Untangle read completion variables · a6e54319
      Peter Hurley authored 
      

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a6e54319
    • Peter Hurley's avatar
      n_tty: Encapsulate minimum_to_wake within N_TTY · f6c8dbe6
      Peter Hurley authored 
      

minimum_to_wake is unique to N_TTY processing, and belongs in
per-ldisc data.

Add the ldisc method, ldisc_ops::fasync(), to notify line disciplines
when signal-driven I/O is enabled or disabled. When enabled for N_TTY
(by fcntl(F_SETFL, O_ASYNC)), blocking reader/polls will be woken
for any readable input. When disabled, blocking reader/polls are not
woken until the read buffer is full.

Canonical mode (L_ICANON(tty), n_tty_data::icanon) is not affected by
the minimum_to_wake setting.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f6c8dbe6
    • Tony Lindgren's avatar
      serial: omap: Fix device tree based PM runtime · a630fbfb
      Tony Lindgren authored 
      

In the runtime_suspend function pdata is not being used, and
also blocks the function in device tree based booting. Fix it
by removing the unused pdata from the runtime_suspend function.

Further, context loss count is not being passed in pdata, so
let's just reinitialize the port every time for those case.
This can be further optimized later on for the device tree
case by adding detection for the hardware state and possibly
by adding a driver specific autosuspend timeout.

And doing this, we can then make the related dev_err into a
dev_dbg message instead of an error.

In order for the wake-up events to work, we also need to set
autosuspend_timeout to -1 if 0, and also device_init_wakeup()
as that's not being done by the platform init code for the
device tree case.

Note that this does not affect legacy booting, and in fact
might make it work for the cases where the context loss info
is not being passed in pdata.

Thanks to Kevin Hilman <khilman@linaro.org> for debugging
and suggesting fixes for the autosuspend_timeout and
device_init_wakeup() related initializiation.

Reviewed-by: default avatarKevin Hilman <khilman@linaro.org>
Tested-by: default avatarKevin Hilman <khilman@linaro.org>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a630fbfb
    • Fabio Estevam's avatar
      serial: imx: Fix serial clock unbalance · 80c48497
      Fabio Estevam authored 
      

Since commit 0c375501 (serial: imx: enable the clocks for console), the
imx_startup() function calls clk_prepare_enable conditionally, so we
need to call clk_disable_unprepare inside imx_shutdown() under the same
condition to avoid unbalanced clock calls.

This avoids the following warning:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 70 at drivers/clk/clk.c:780 __clk_disable+0x68/0x84()
Modules linked in:
CPU: 0 PID: 70 Comm: mountall Not tainted 3.10.0-rc4-next-20130607+ #435
Backtrace:
[<800116a4>] (dump_backtrace+0x0/0x10c) from [<80011844>] (show_stack+0x18/0x1c)
 r6:8069f4e8 r5:0000030c r4:00000000 r3:00000000
[<8001182c>] (show_stack+0x0/0x1c) from [<8053bce0>] (dump_stack+0x78/0x94)
[<8053bc68>] (dump_stack+0x0/0x94) from [<80023df8>] (warn_slowpath_common+0x6c/0x8c)
 r4:00000000 r3:00000000
[<80023d8c>] (warn_slowpath_common+0x0/0x8c) from [<80023e3c>] (warn_slowpath_null+0x24/0x2c)
 r8:bf2ed008 r7:bfaa9810 r6:000f0013 r5:bf824b80 r4:bf824b80
[<80023e18>] (warn_slowpath_null+0x0/0x2c) from [<8041af84>] (__clk_disable+0x68/0x84)
[<8041af1c>] (__clk_disable+0x0/0x84) from [<8041b098>] (clk_disable+0x20/0x2c)
 r4:600f0013 r3:00000001
[<8041b078>] (clk_disable+0x0/0x2c) from [<802c93e8>] (imx_shutdown+0xbc/0xec)
 r5:bf824b80 r4:bfaa9810
[<802c932c>] (imx_shutdown+0x0/0xec) from [<802c63a0>] (uart_port_shutdown+0x34/0x40)
 r5:bf86f860 r4:bfaa9810
[<802c636c>] (uart_port_shutdown+0x0/0x40) from [<802c68c0>] (uart_shutdown+0x98/0xc4)
 r4:bf86f800 r3:00000000
[<802c6828>] (uart_shutdown+0x0/0xc4) from [<802c7514>] (uart_close+0x5c/0x198)
 r7:bfaa9810 r6:bf274400 r5:bf86f86c r4:bf86f800
[<802c74b8>] (uart_close+0x0/0x198) from [<802ac648>] (tty_release+0xf8/0x500)
[<802ac550>] (tty_release+0x0/0x500) from [<800c5a30>] (__fput+0x9c/0x208)
[<800c5994>] (__fput+0x0/0x208) from [<800c5bac>] (____fput+0x10/0x14)
[<800c5b9c>] (____fput+0x0/0x14) from [<80040234>] (task_work_run+0xb4/0xec)
[<80040180>] (task_work_run+0x0/0xec) from [<80029238>] (do_exit+0x2b0/0x920)
 r8:8000e144 r7:000000f8 r6:bf306300 r5:00000000 r4:bfac1180
[<80028f88>] (do_exit+0x0/0x920) from [<80029a4c>] (do_group_exit+0x50/0xd4)
 r7:000000f8
[<800299fc>] (do_group_exit+0x0/0xd4) from [<80029ae8>] (__wake_up_parent+0x0/0x28)
 r7:000000f8 r6:00000001 r5:0006f7ae r4:0006f79a
[<80029ad0>] (SyS_exit_group+0x0/0x18) from [<8000dfc0>] (ret_fast_syscall+0x0/0x30)
---[ end trace 16d080eb7efea4e9 ]---

Reported-by: default avatarShawn Guo <shawn.guo@linaro.org>
Signed-off-by: default avatarFabio Estevam <fabio.estevam@freescale.com>
Tested-by: default avatarShawn Guo <shawn.guo@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      80c48497
    • Matteo Facchinetti's avatar
      serial/mpc52xx_uart: fix kernel panic when system reboot · 8a29dfb8
      Matteo Facchinetti authored 
      

This bug appear when a second PSC based driver appends an interrupt
routine to the FIFO controller shared interrupt (like spi-mpc512x-psc).
When reboot, uart_shutdown() remove the serial console interrupt handler
while spi-mpc512x-psc isr is still activate and cause the following kernel
panic:

The system is going down for reboot NOW!rpc (ttyPSC0) (Mon Jun 10 12:26:07 20
INIT: Sending processirq 40: nobody cared (try booting with the "irqpoll" option)
CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0-rc4-next-20130607-00001-ga0bceb3-dirty #5
Call Trace:
[cfff9f00] [c0007910] show_stack+0x48/0x150 (unreliable)
[cfff9f40] [c005ae60] __report_bad_irq.isra.6+0x34/0xe0
[cfff9f60] [c005b194] note_interrupt+0x214/0x26c
[cfff9f90] [c00590fc] handle_irq_event_percpu+0xd0/0x1bc
[cfff9fd0] [c005921c] handle_irq_event+0x34/0x54
[cfff9fe0] [c005b8f4] handle_level_irq+0x90/0xf4
[cfff9ff0] [c000cb98] call_handle_irq+0x18/0x28
[c050dd60] [c000575c] do_IRQ+0xcc/0x124
[c050dd90] [c000eb04] ret_from_except+0x0/0x14

Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8a29dfb8
    • Feng Tang's avatar
      serial: mfd: Add sysrq support · fcd2bb9b
      Feng Tang authored 
      

When using MFD HSU based console, sometime we need the sysrq function
to help debugging kernel. The sysrq code is basically there, this
patch just simply enable it.

Signed-off-by: default avatarFeng Tang <feng.tang@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      fcd2bb9b
    • Peter Hurley's avatar
      tty: Fix transient pty write() EIO · 7c61c3d8
      Peter Hurley authored 
      

Commit 69939035
('pty: Ignore slave pty close() if never successfully opened')
introduced a bug with ptys whereby a write() in parallel with an
open() on an existing pty could mistakenly indicate an I/O error.

Only indicate an I/O error if the condition on open() actually exists.

Reported-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Tested-by: default avatarMikael Pettersson <mikpe@it.uu.se>
Cc: stable <stable@vger.kernel.org> # 3.9
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7c61c3d8
    • Ross Lagerwall's avatar
      tty/vt: Return EBUSY if deallocating VT1 and it is busy · ef223fb3
      Ross Lagerwall authored 
      

Commit 421b40a6 ("tty/vt: Fix vc_deallocate() lock order") changed
the behavior when deallocating VT 1.  Previously if trying to
deallocate VT1 and it is busy, we would return EBUSY.  The commit
changed this to return 0 (success).

This commit restores the old behavior.

Signed-off-by: default avatarRoss Lagerwall <rosslagerwall@gmail.com>
Tested-by: default avatarMikael Pettersson <mikpe@it.uu.se>
Acked-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ef223fb3
  5. Jun 09, 2013
  7. Jun 06, 2013
  9. Jun 03, 2013
  11. May 22, 2013
  13. May 21, 2013
  15. May 20, 2013
    • Peter Hurley's avatar
      tty: Add timed, writer-prioritized rw semaphore · 4898e640
      Peter Hurley authored 
      

The semantics of a rw semaphore are almost ideally suited
for tty line discipline lifetime management;  multiple active
threads obtain "references" (read locks) while performing i/o
to prevent the loss or change of the current line discipline
(write lock).

Unfortunately, the existing rw_semaphore is ill-suited in other
ways;
1) TIOCSETD ioctl (change line discipline) expects to return an
   error if the line discipline cannot be exclusively locked within
   5 secs. Lock wait timeouts are not supported by rwsem.
2) A tty hangup is expected to halt and scrap pending i/o, so
   exclusive locking must be prioritized.
   Writer priority is not supported by rwsem.

Add ld_semaphore which implements these requirements in a
semantically similar way to rw_semaphore.

Writer priority is handled by separate wait lists for readers and
writers. Pending write waits are priortized before existing read
waits and prevent further read locks.

Wait timeouts are trivially added, but obviously change the lock
semantics as lock attempts can fail (but only due to timeout).

This implementation incorporates the write-lock stealing work of
Michel Lespinasse <walken@google.com>.

Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4898e640
    • Wang YanQing's avatar
      vt: delete unneeded function unregister_con_driver · 50539dd4
      Wang YanQing authored 
      

Now there is no place use unregister_con_driver,
and we can achieve unregister_con_driver's function
with unregister_con_driver easily, so just delete it
to reduce code size and duplication.

Signed-off-by: default avatarWang YanQing <udknight@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      50539dd4