linux-kernel - Re: [PATCH] ASoC: da7219: Improve the relability of AAD IRQ process

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Message-ID: <CABXOdTfGD_fyi+itsr9Nd834Pb6+4Ej8M9SM5AN=uhXQ1K4DiA@mail.gmail.com>
Date:   Tue, 11 Apr 2023 07:28:06 -0700
From:   Guenter Roeck <groeck@...gle.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     David Rau <David.Rau.opensource@...renesas.com>,
        support.opensource@...semi.com, lgirdwood@...il.com,
        perex@...ex.cz, tiwai@...e.com, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org, bailideng@...gle.com
Subject: Re: [PATCH] ASoC: da7219: Improve the relability of AAD IRQ process

On Tue, Apr 11, 2023 at 4:32 AM Mark Brown <broonie@...nel.org> wrote:
>
> On Mon, Apr 10, 2023 at 09:26:34AM +0000, David Rau wrote:
>
> > This commit improves the control of ground switches in AAD IRQ
>
> In what way does it do this - what was previously unrelabile and how
> does this change address that?

One very specific problem is that da7219_aad_handle_gnd_switch_time()
is currently called after interrupts were enabled. As a result, the
delay time is not initialized if there is an interrupt before the
initialization. This results in a negative value passed to msleep().
Since the parameter to msleep() is unsigned, this causes it to sleep
forever which in turn causes a substantial number of hung task crashes
in ChromeOS. Plus, of course, the code doesn't really do anything in
this situation.

A secondary problem may be that calling msleep() with a potentially
large sleep time on a system worker isn't really a good idea, but I
didn't explore the impact further.

Guenter