linux-stable.git/drivers/tty/serial/serial_core.c, branch linux-3.1.y

serial-core: power up uart port early before we do set_termios when resuming

2011-11-11T17:42:18+00:00

commit 94abc56f4d90f289ea32a0a11d3577fcd8cb28fb upstream.

The following patch removed uart_change_pm() in uart_resume_port():

commit 5933a161abcb8d83a2c145177f48027c3c0a8995
Author: Yin Kangkai 
    serial-core: reset the console speed on resume

It will break the pxa serial driver when the system resumes from suspend mode
as it will try to set baud rate divider register in set_termios but with
clock off. The register value can not be set correctly on some platform if
the clock is disabled. The pxa driver will check the value and report the
following warning:

------------[ cut here ]------------
WARNING: at drivers/tty/serial/pxa.c:545 serial_pxa_set_termios+0x1dc/0x250()
Modules linked in:
[] (unwind_backtrace+0x0/0xf0) from [] (warn_slowpath_common+0x4c/0x64)
[] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_null+0x18/0x1c)
[] (warn_slowpath_null+0x18/0x1c) from [] (serial_pxa_set_termios+0x1dc/0x250)
[] (serial_pxa_set_termios+0x1dc/0x250) from [] (uart_resume_port+0x128/0x2dc)
[] (uart_resume_port+0x128/0x2dc) from [] (serial_pxa_resume+0x18/0x24)
[] (serial_pxa_resume+0x18/0x24) from [] (platform_pm_resume+0x40/0x4c)
[] (platform_pm_resume+0x40/0x4c) from [] (pm_op+0x68/0xb4)
[] (pm_op+0x68/0xb4) from [] (device_resume+0xb0/0xec)
[] (device_resume+0xb0/0xec) from [] (dpm_resume+0xe0/0x194)
[] (dpm_resume+0xe0/0x194) from [] (dpm_resume_end+0xc/0x18)
[] (dpm_resume_end+0xc/0x18) from [] (suspend_devices_and_enter+0x16c/0x1ac)
[] (suspend_devices_and_enter+0x16c/0x1ac) from [] (enter_state+0xac/0xdc)
[] (enter_state+0xac/0xdc) from [] (state_store+0xa0/0xbc)
[] (state_store+0xa0/0xbc) from [] (kobj_attr_store+0x18/0x1c)
[] (kobj_attr_store+0x18/0x1c) from [] (sysfs_write_file+0x108/0x140)
[] (sysfs_write_file+0x108/0x140) from [] (vfs_write+0xac/0x134)
[] (vfs_write+0xac/0x134) from [] (sys_write+0x3c/0x68)
[] (sys_write+0x3c/0x68) from [] (ret_fast_syscall+0x0/0x2c)
---[ end trace 88289eceb4675b04 ]---

This patch fix the problem by adding the power on opertion back for uart
console when console_suspend_enabled is true.

Signed-off-by: Ning Jiang 
Tested-by: Mayank Rana 
Signed-off-by: Greg Kroah-Hartman

TTY: serial, document ignoring of uart->ops->startup error

2011-08-23T17:10:38+00:00

When a user has SYS_ADMIN capabilities and uart->ops->startup returns
an error in uart_startup, we silently drop the error. We then return 0
and behave as if it didn't fail. (Not quite, since we set TTY_IO_ERROR
bit and leave ASYNC_INITIALIZED bit cleared.)

This all is to allow setserial to work with improperly configured or
unconfigured ports. User can thus set port properties and reconfigure
properly.

This patch only documents this behavior.

Signed-off-by: Jiri Slaby 
Cc: Alan Cox 
Cc: Russel King 
Signed-off-by: Greg Kroah-Hartman

TTY: serial_core, remove superfluous set_task_state

2011-04-25T21:19:12+00:00

msleep* is guaranteed to return with TASK_RUNNING task state. And
since there is no other set_task_state in the paths of
uart_wait_until_sent, we need not to set_task_state to TASK_RUNNING.

Signed-off-by: Jiri Slaby 
Cc: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

TTY: serial_core, remove invalid test

2011-04-25T21:19:11+00:00

tty->index (named here as line) is set up in initialize_tty_struct.
The value is checked in get_tty_driver for the found driver as:
	if (device < base || device >= base + p->num)
		continue;
	*index = device - base;

So index/line can never be more than driver->num. Hence remove this
test from uart_open.

Signed-off-by: Jiri Slaby 
Cc: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

Serial: Remove unused code.

2011-04-19T23:33:37+00:00

Remove stale code in serial_core layer.

Cc: Alan Cox 
Signed-off-by: Govindraj.R 
Signed-off-by: Greg Kroah-Hartman

tty: remove invalid location line in file header

2011-04-19T23:33:36+00:00

remove invalid location line in each file header after location
moved from driver/char to driver/tty

Signed-off-by: Jovi Zhang 
Signed-off-by: Greg Kroah-Hartman

serial: core, remove uart_update_termios

2011-04-19T23:32:20+00:00

Now, uart_update_termios is empty, so it's time to remove it. We no
longer need a live tty in .dtr_rts. So this should prune all the bugs
where tty is zeroed in port->tty during tty_port_block_til_ready.

There is one thing to note. We don't set ASYNC_NORMAL_ACTIVE now. It's
because this is done already in tty_port_block_til_ready.

Signed-off-by: Jiri Slaby 
Cc: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

serial: core, do not set DTR/RTS twice on startup

2011-04-19T23:32:20+00:00

In .dtr_rts we do:
  uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS)
and call uart_update_termios. It does:
  uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS)
once again. As the only callsite of uart_update_termios is .dtr_rts,
remove the uart_set_mctrl from uart_update_termios to not set it twice.

Signed-off-by: Jiri Slaby 
Cc: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

serial: core, move termios handling to uart_startup

2011-04-19T23:32:20+00:00

We should not fiddle with speed and cflags in .dtr_rts hook. Actually
we might not have tty at that moment already.

So move the console cflag copy and speed setup into uart_startup.
Actually the speed setup is already there, but we need to call it
unconditionally (uart_startup is called from uart_open with hw_init =
0).

This means we move uart_change_speed before dtr/rts setup in .dtr_rts.
But this should not matter as the setup should be called after
uart_change_speed anyway.
Before:                             After:
dtr/rts setup (dtr_rts)             uart_change_speed (startup)
uart_change_speed (update_termios)  dtr/rts setup (dtr_rts)
dtr/rts setup (update_termios)      dtr/rts setup (update_termios)

The second setup will dismiss with the next patch.

Signed-off-by: Jiri Slaby 
Cc: Alan Cox 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

TTY: serial_core, remove unused variable

2011-04-19T21:41:47+00:00

drivers/tty/serial/serial_core.c:1980:2: warning: Value stored to 'tty' is never read
        tty = port->tty;
        ^     ~~~~~~~~~

Signed-off-by: Jiri Slaby 
Acked-by: Govindraj.R 
Signed-off-by: Greg Kroah-Hartman