linux-kernel - Re: [V4] serial: core: Do stop_rx in suspend path for console if console

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Date:   Tue, 7 Jun 2022 18:55:49 +0530
From:   Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
To:     Greg KH <gregkh@...uxfoundation.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>
CC:     <jirislaby@...nel.org>, <linux-serial@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_msavaliy@...cinc.com>,
        <dianders@...omium.org>, <mka@...omium.org>, <swboyd@...omium.org>
Subject: Re: [V4] serial: core: Do stop_rx in suspend path for console if
 console_suspend is disabled


On 6/7/2022 6:52 PM, Greg KH wrote:
> On Mon, May 23, 2022 at 11:32:46PM +0200, Marek Szyprowski wrote:
>> Hi,
>>
>> On 16.05.2022 11:20, 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, during
>>> resume, rx transactions can 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.
>>>
>>> Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
>>> ---
>>> v4: moved the change to serial core to apply for all drivers
>>> v3: swapped the order of conditions to be more human readable
>>> v2: restricted patch to contain only stop_rx in suspend sequence
>>> v1: intial patch contained 2 additional unrelated changes in vicinity
>>> ---
>> This patch landed recently in linux-next as commit c9d2325cdb92
>> ("serial: core: Do stop_rx in suspend path for console if
>> console_suspend is disabled").
>>
>> Unfortunately it breaks console operation on my test systems after
>> system suspend/resume cycle if 'no_console_suspend' kernel parameter is
>> present. System properly resumes from suspend, the console displays all
>> the messages and even command line prompt, but then doesn't react on any
>> input. If I remove the 'no_console_suspend' parameter, the console is
>> again operational after system suspend/resume cycle. Before this patch
>> it worked fine regardless the 'no_console_suspend' parameter.
> Did this ever get resolved or do I need to revert this?

We have a resolution and I will be uploading a Fixes: patch today.

Thank you.

-Vijay/


>
> thanks,
>
> greg k-h