linux-kernel - Re: [PATCH] mfd: axp20x: Do not sleep in the power off handler

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Message-ID: <a3488b0c-dbc7-0109-8ba7-9f319f018e22@collabora.com>
Date:   Mon, 7 Nov 2022 01:40:17 +0300
From:   Dmitry Osipenko <dmitry.osipenko@...labora.com>
To:     Samuel Holland <samuel@...lland.org>, Chen-Yu Tsai <wens@...e.org>,
        Lee Jones <lee@...nel.org>
Cc:     Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mfd: axp20x: Do not sleep in the power off handler

On 11/6/22 00:29, Samuel Holland wrote:
> Since commit 856c288b0039 ("ARM: Use do_kernel_power_off()"), the
> function axp20x_power_off() now runs inside a RCU read-side critical
> section, so it is not allowed to call msleep(). Use mdelay() instead.
> 
> Fixes: 856c288b0039 ("ARM: Use do_kernel_power_off()")
> Signed-off-by: Samuel Holland <samuel@...lland.org>
> ---
> 
>  drivers/mfd/axp20x.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index 88a212a8168c..880c41fa7021 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -842,7 +842,7 @@ static void axp20x_power_off(void)
>  		     AXP20X_OFF);
>  
>  	/* Give capacitors etc. time to drain to avoid kernel panic msg. */
> -	msleep(500);
> +	mdelay(500);
>  }
>  
>  int axp20x_match_device(struct axp20x_dev *axp20x)

ARM was doing local_irq_disable() on power-off before
do_kernel_power_off() was introduced, so this should've been incorrect
for a couple years at least. If I'm not missing anything.

-- 
Best regards,
Dmitry