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From: Guenter Roeck <linux@roeck-us.net>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>,
	Knud Poulsen <knpo@ieee.org>,
	linux-watchdog@vger.kernel.org, kernel@pengutronix.de,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 4/8] watchdog: f71808e_wdt: clear watchdog timeout occurred flag
Date: Tue, 30 Jun 2020 14:09:24 -0700
Message-ID: <20200630210924.GA23191@roeck-us.net> (raw)
In-Reply-To: <20200611191750.28096-5-a.fatoum@pengutronix.de>

On Thu, Jun 11, 2020 at 09:17:45PM +0200, Ahmad Fatoum wrote:
> The flag indicating a watchdog timeout having occurred normally persists
> till Power-On Reset of the Fintek Super I/O chip. The user can clear it
> by writing a `1' to the bit.
> 
> The driver doesn't offer a restart method, so regular system reboot
> might not reset the Super I/O and if the watchdog isn't enabled, we
> won't touch the register containing the bit on the next boot.
> In this case all subsequent regular reboots will be wrongly flagged
> by the driver as being caused by the watchdog.
> 
> Fix this by having the flag cleared after read. This is also done by
> other drivers like those for the i6300esb and mpc8xxx_wdt.
> 
> Fixes: b97cb21a4634 ("watchdog: f71808e_wdt: Fix WDTMOUT_STS register read")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/watchdog/f71808e_wdt.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
> index 8e5584c54423..26bf366aebc2 100644
> --- a/drivers/watchdog/f71808e_wdt.c
> +++ b/drivers/watchdog/f71808e_wdt.c
> @@ -706,6 +706,13 @@ static int __init watchdog_init(int sioaddr)
>  	wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF);
>  	watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS);
>  
> +	/*
> +	 * We don't want WDTMOUT_STS to stick around till regular reboot.
> +	 * Write 1 to the bit to clear it to zero.
> +	 */
> +	superio_outb(sioaddr, F71808FG_REG_WDT_CONF,
> +		     wdt_conf | BIT(F71808FG_FLAG_WDTMOUT_STS));
> +
>  	superio_exit(sioaddr);
>  
>  	err = watchdog_set_timeout(timeout);

  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-11 19:17 [PATCH v1 0/8] watchdog: f71808e_wdt: migrate to kernel Ahmad Fatoum
2020-06-11 19:17 ` [PATCH v1 1/8] docs: watchdog: codify ident.options as superset of possible status flags Ahmad Fatoum
2020-06-30 20:49   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 2/8] watchdog: f71808e_wdt: indicate WDIOF_CARDRESET support in watchdog_info.options Ahmad Fatoum
2020-06-30 20:51   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 3/8] watchdog: f71808e_wdt: remove use of wrong watchdog_info option Ahmad Fatoum
2020-06-30 21:07   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 4/8] watchdog: f71808e_wdt: clear watchdog timeout occurred flag Ahmad Fatoum
2020-06-30 21:09   ` Guenter Roeck [this message]
2020-06-11 19:17 ` [PATCH v1 5/8] watchdog: f71808e_wdt: do stricter parameter validation Ahmad Fatoum
2020-06-30 21:11   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 6/8] watchdog: f71808e_wdt: consolidate variant handling into single array Ahmad Fatoum
2020-06-30 21:18   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 7/8] watchdog: f71808e_wdt: migrate to new kernel watchdog API Ahmad Fatoum
2020-06-30 21:26   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 8/8] watchdog: f71808e_wdt: rename variant-independent identifiers appropriately Ahmad Fatoum
2020-06-12  4:57   ` kernel test robot
2020-06-12  4:57   ` [RFC PATCH] watchdog: f71808e_wdt: fintek_variants[] can be static kernel test robot
2020-06-30 21:29   ` [PATCH v1 8/8] watchdog: f71808e_wdt: rename variant-independent identifiers appropriately Guenter Roeck

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