linux-kernel - Re: [PATCHv3 0/4] Get rid of pm_runtime_irq_safe() for 8250

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Date:   Mon, 18 Oct 2021 09:11:42 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andriy.shevchenko@...el.com>,
        Jiri Slaby <jirislaby@...nel.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-serial@...r.kernel.org, linux-omap@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3 0/4] Get rid of pm_runtime_irq_safe() for 8250_omap

On Fri, Oct 15, 2021 at 02:26:22PM +0300, Tony Lindgren wrote:
> Hi,
> 
> Here are v3 patches to get rid of pm_runtime_irq_safe() for the 8250_omap
> driver. Based on comments from Andy, Johan and Greg, I improved a bunch of
> things as listed below.
> 
> For removing the pm_runtime_irq_safe() usage, serial TX is the last
> remaining issue. We deal with TX by waking up the port and returning 0
> bytes written from write_room() and write() if the port is not available
> because of PM runtime autoidle.

Oh, there's a lot more than TX that needs fixing... And I believe the
second sentence no longer applies since v1.

> Chganges since v2:
> 
> - Use locking instead of atomic_t as suggested by Greg
> 
> Changes since v1:
> 
> - Separated out line discipline patches, n_tty -EAGAIN change I still
>   need to retest
> 
> - Changed prep_tx() to more generic wakeup() as also flow control needs it
> 
> - Changed over to using wakeup() with device driver runtime PM instead
>   of write_room()
> 
> - Added runtime_suspended flag for drivers and generic serial layer PM
>   to use

Johan