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:3.255 / U:0.000 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site