linux-kernel - Re: [PATCH] mfd: stpmic1: Attempt system shutdown twice in case PMIC is confused

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20260113123322.GI1902656@google.com>
Date: Tue, 13 Jan 2026 12:33:22 +0000
From: Lee Jones <lee@...nel.org>
To: Marek Vasut <marex@...ladev.com>
Cc: linux-kernel@...r.kernel.org, Pascal PAILLET-LME <p.paillet@...com>,
	Paul Cercueil <paul@...pouillou.net>,
	Sean Nyekjaer <sean@...nix.com>, kernel@...electronics.com
Subject: Re: [PATCH] mfd: stpmic1: Attempt system shutdown twice in case PMIC
 is confused

On Fri, 09 Jan 2026, Marek Vasut wrote:

> Attempt to shut down again, in case the first attempt failed.
> The STPMIC1 might get confused and the first regmap_update_bits()
> returns with -ETIMEDOUT / -110 . If that or similar transient
> failure occurs, try to shut down again. If the second attempt
> fails, there is some bigger problem, report it to user.
> 
> Fixes: 6e9df38f359a ("mfd: stpmic1: Add PMIC poweroff via sys-off handler")
> Signed-off-by: Marek Vasut <marex@...ladev.com>
> ---
> Cc: Lee Jones <lee@...nel.org>
> Cc: Pascal PAILLET-LME <p.paillet@...com>
> Cc: Paul Cercueil <paul@...pouillou.net>
> Cc: Sean Nyekjaer <sean@...nix.com>
> Cc: kernel@...electronics.com
> ---
>  drivers/mfd/stpmic1.c | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mfd/stpmic1.c b/drivers/mfd/stpmic1.c
> index 081827bc05961..9ef4049d7db10 100644
> --- a/drivers/mfd/stpmic1.c
> +++ b/drivers/mfd/stpmic1.c
> @@ -121,9 +121,23 @@ static const struct regmap_irq_chip stpmic1_regmap_irq_chip = {
>  static int stpmic1_power_off(struct sys_off_data *data)
>  {
>  	struct stpmic1 *ddata = data->cb_data;
> +	int ret;
> +
> +	ret = regmap_update_bits(ddata->regmap, MAIN_CR, SOFTWARE_SWITCH_OFF, SOFTWARE_SWITCH_OFF);
> +	if (!ret)
> +		return NOTIFY_DONE;
> +
> +	/*
> +	 * Attempt to shut down again, in case the first attempt failed.
> +	 * The STPMIC1 might get confused and the first regmap_update_bits()
> +	 * returns with -ETIMEDOUT / -110 . If that or similar transient
> +	 * failure occurs, try to shut down again. If the second attempt
> +	 * fails, there is some bigger problem, report it to user.
> +	 */
> +	ret = regmap_update_bits(ddata->regmap, MAIN_CR, SOFTWARE_SWITCH_OFF, SOFTWARE_SWITCH_OFF);

I think it would be better to put it into a loop with 2 retries.

> +	if (ret)
> +		dev_err(ddata->dev, "Failed to access PMIC I2C bus (%d)\n", ret);
>  
> -	regmap_update_bits(ddata->regmap, MAIN_CR,
> -			   SOFTWARE_SWITCH_OFF, SOFTWARE_SWITCH_OFF);
>  
>  	return NOTIFY_DONE;
>  }
> -- 
> 2.51.0
> 

-- 
Lee Jones [李琼斯]