From: Guenter Roeck <linux@roeck-us.net>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Georg Hofmann <georg@hofmannsweb.com>,
linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] watchdog: imx2_wdt: fix min() calculation in imx2_wdt_set_timeout
Date: Mon, 12 Aug 2019 06:28:05 -0700 [thread overview]
Message-ID: <77faf1bd-14cc-831f-e65e-4f2aa74e1843@roeck-us.net> (raw)
In-Reply-To: <20190812131356.23039-1-linux@rasmusvillemoes.dk>
On 8/12/19 6:13 AM, Rasmus Villemoes wrote:
> Converting from ms to s requires dividing by 1000, not multiplying. So
> this is currently taking the smaller of new_timeout and 1.28e8,
> i.e. effectively new_timeout.
>
> The driver knows what it set max_hw_heartbeat_ms to, so use that
> value instead of doing a division at run-time.
>
> FWIW, this can easily be tested by booting into a busybox shell and
> doing "watchdog -t 5 -T 130 /dev/watchdog" - without this patch, the
> watchdog fires after 130&127 == 2 seconds.
>
> Fixes: b07e228eee69 "watchdog: imx2_wdt: Fix set_timeout for big timeout values"
> Cc: stable@vger.kernel.org # 5.2 plus anything the above got backported to
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> This should really be handled in the watchdog core for any driver that
> reports max_hw_heartbeat_ms.
>
Good point. I'll see if I can write a patch.
Guenter
> The same pattern appears in aspeed_wdt.c. I don't have the hardware, but
> s#wdd->max_hw_heartbeat_ms * 1000#WDT_MAX_TIMEOUT_MS/1000U# should fix that one.
>
>
> drivers/watchdog/imx2_wdt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> index 32af3974e6bb..8d019a961ccc 100644
> --- a/drivers/watchdog/imx2_wdt.c
> +++ b/drivers/watchdog/imx2_wdt.c
> @@ -55,7 +55,7 @@
>
> #define IMX2_WDT_WMCR 0x08 /* Misc Register */
>
> -#define IMX2_WDT_MAX_TIME 128
> +#define IMX2_WDT_MAX_TIME 128U
> #define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */
>
> #define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)
> @@ -180,7 +180,7 @@ static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
> {
> unsigned int actual;
>
> - actual = min(new_timeout, wdog->max_hw_heartbeat_ms * 1000);
> + actual = min(new_timeout, IMX2_WDT_MAX_TIME);
> __imx2_wdt_set_timeout(wdog, actual);
> wdog->timeout = new_timeout;
> return 0;
>
next prev parent reply other threads:[~2019-08-12 13:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 13:13 [PATCH] watchdog: imx2_wdt: fix min() calculation in imx2_wdt_set_timeout Rasmus Villemoes
2019-08-12 13:28 ` Guenter Roeck [this message]
2019-08-26 12:05 ` Rasmus Villemoes
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