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

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Date:   Mon, 6 Jun 2022 18:00:39 +0530
From:   Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
To:     Doug Anderson <dianders@...omium.org>
CC:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        <linux-serial@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, <quic_msavaliy@...cinc.com>,
        Matthias Kaehlcke <mka@...omium.org>,
        "Stephen Boyd" <swboyd@...omium.org>
Subject: Re: [V4] serial: core: Do stop_rx in suspend path for console if
 console_suspend is disabled

Hi,


On 6/4/2022 12:58 AM, Doug Anderson wrote:
> Hi,
>
> On Fri, Jun 3, 2022 at 11:54 AM Vijaya Krishna Nivarthi
> <quic_vnivarth@...cinc.com> wrote:
>>>>> Add a start_rx in uart_resume_port after call to set_termios to handle
>>>>> this scenario for other drivers.
>> Since start_rx is not exposed it doesn't seem like we will be able to
>> handle it in core.
>>
>> In your drivers, Can we add a call to stop_rx at begin of set_termios
>> and then undo it at end?
>>
>> That would ensure that set_termios functionality is unaffected while
>> fixing the broken cases?
>>
>> If that's not an option we will have to go back to a previous version of
>> limiting the change to qcom driver.
> How about this: add an optional start_rx() callback to "struct
> uart_ops" and then only do your stop_rx() logic in uart_suspend_port()
> if you'll be able to start it again (AKA if the start_rx() callback is
> not NULL). That keeps the logic in the core.

This seems good. Thank you.

And also conditionally call start_rx in uart_resume_port after call to 
set_termios?
I have tested such patch and it is working fine, will upload it.

-Vijay/

> -Doug