lkml.org 
[lkml]   [2022]   [Apr]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [V3] drivers/tty/serial/qcom-geni-serial: Do stop_rx in suspend path for console if console_suspend is disabled
From

On 4/7/2022 1:21 PM, Jiri Slaby wrote:
> On 07. 04. 22, 9:25, Vijaya Krishna Nivarthi wrote:
>> For the case of console_suspend disabled, if back to back suspend/resume
>> test is executed, at the end of test, sometimes console would appear to
>> be frozen not responding to input. This would happen because, for
>> console_suspend disabled, suspend/resume routines only turn resources
>> off/on but don't do a port close/open.
>> As a result, during resume, some rx transactions come in before
>> system is
>> ready, malfunction of rx happens in turn resulting in console appearing
>> to be stuck.
>>
>> Do a stop_rx in suspend sequence to prevent this. start_rx is already
>> present in resume sequence as part of call to set_termios which does a
>> stop_rx/start_rx.
>
> So why is it OK for every other driver? Should uart_suspend_port() be
> fixed instead?

For qcom driver we know that set_termios() call in uart_suspend_port()
will recover with a call to start_rx.
However that may not be the case with other drivers.

We can move stop_rx to uart_suspend_port() and additionally have a
start_rx in uart_resume_port()
Please let know if such a change would be ok.
Thank you.


\
 
 \ /
  Last update: 2022-04-08 08:19    [W:0.066 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site