Re: [PATCH 2/2] serial: core: Preserve termios c_cflag for console resume

From: Peter Hurley
Date: Wed Jun 04 2014 - 10:46:54 EST

On 06/04/2014 10:22 AM, Greg Kroah-Hartman wrote:
On Wed, Jun 04, 2014 at 10:16:11AM -0400, Peter Hurley wrote:
When a tty is opened for the serial console, the termios c_cflag
settings are inherited from the console line settings.
However, if the tty is subsequently closed, the termios settings
are lost. This results in a garbled console if the console is later
suspended and resumed.

Preserve the termios c_cflag for the serial console when the tty
is shutdown; this reflects the most recent line settings.

Fixes: Bugzilla #69751, 'serial console does not wake from S3'
Reported-by: Valerio Vanni <valerio.vanni@xxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
drivers/tty/serial/serial_core.c | 3 +++
1 file changed, 3 insertions(+)

Same as before, regression, or just a normal "new feature"?

This was reported as a regression since 2.6.24, but that was likely
misreported, and more likely due to a userspace update which triggers
the bug.

I would be surprised if console resume _never_ worked if the serial tty
was opened then closed, but it probably has worked for a long time.

Peter Hurley

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