* [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout"
@ 2021-10-08 0:33 Guenter Roeck
2021-10-08 7:52 ` Jan Kiszka
2021-10-20 19:44 ` Guenter Roeck
0 siblings, 2 replies; 5+ messages in thread
From: Guenter Roeck @ 2021-10-08 0:33 UTC (permalink / raw)
To: Wim Van Sebroeck
Cc: linux-watchdog, linux-kernel, Guenter Roeck, Jan Kiszka,
Mantas Mikulėnas, Javier S . Pedro
This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for
rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt:
Fix detection of SMI-off case") since those patches cause a regression
on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809).
While this revert may result in some boards to only reset after twice
the configured timeout value, that is still better than a watchdog reset
after half the configured value.
Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout")
Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case")
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Mantas Mikulėnas <grawity@gmail.com>
Reported-by: Javier S. Pedro <debbugs@javispedro.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/watchdog/iTCO_wdt.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 643c6c2d0b72..ced2fc0deb8c 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -71,8 +71,6 @@
#define TCOBASE(p) ((p)->tco_res->start)
/* SMI Control and Enable Register */
#define SMI_EN(p) ((p)->smi_res->start)
-#define TCO_EN (1 << 13)
-#define GBL_SMI_EN (1 << 0)
#define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
#define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
@@ -357,12 +355,8 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
tmrval = seconds_to_ticks(p, t);
- /*
- * If TCO SMIs are off, the timer counts down twice before rebooting.
- * Otherwise, the BIOS generally reboots when the SMI triggers.
- */
- if (p->smi_res &&
- (inl(SMI_EN(p)) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
+ /* For TCO v1 the timer counts down twice before rebooting */
+ if (p->iTCO_version == 1)
tmrval /= 2;
/* from the specs: */
@@ -527,7 +521,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
* Disables TCO logic generating an SMI#
*/
val32 = inl(SMI_EN(p));
- val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */
+ val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */
outl(val32, SMI_EN(p));
}
--
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout"
2021-10-08 0:33 [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout" Guenter Roeck
@ 2021-10-08 7:52 ` Jan Kiszka
2021-10-08 13:05 ` Guenter Roeck
2021-10-20 19:44 ` Guenter Roeck
1 sibling, 1 reply; 5+ messages in thread
From: Jan Kiszka @ 2021-10-08 7:52 UTC (permalink / raw)
To: Guenter Roeck, Wim Van Sebroeck
Cc: linux-watchdog, linux-kernel, Mantas Mikulėnas, Javier S . Pedro
On 08.10.21 02:33, Guenter Roeck wrote:
> This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for
> rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt:
> Fix detection of SMI-off case") since those patches cause a regression
> on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809).
>
> While this revert may result in some boards to only reset after twice
> the configured timeout value, that is still better than a watchdog reset
> after half the configured value.
>
> Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout")
> Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case")
> Cc: Jan Kiszka <jan.kiszka@siemens.com>
> Cc: Mantas Mikulėnas <grawity@gmail.com>
> Reported-by: Javier S. Pedro <debbugs@javispedro.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> drivers/watchdog/iTCO_wdt.c | 12 +++---------
> 1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> index 643c6c2d0b72..ced2fc0deb8c 100644
> --- a/drivers/watchdog/iTCO_wdt.c
> +++ b/drivers/watchdog/iTCO_wdt.c
> @@ -71,8 +71,6 @@
> #define TCOBASE(p) ((p)->tco_res->start)
> /* SMI Control and Enable Register */
> #define SMI_EN(p) ((p)->smi_res->start)
> -#define TCO_EN (1 << 13)
> -#define GBL_SMI_EN (1 << 0)
>
> #define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
> #define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
> @@ -357,12 +355,8 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
>
> tmrval = seconds_to_ticks(p, t);
>
> - /*
> - * If TCO SMIs are off, the timer counts down twice before rebooting.
> - * Otherwise, the BIOS generally reboots when the SMI triggers.
> - */
> - if (p->smi_res &&
> - (inl(SMI_EN(p)) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
> + /* For TCO v1 the timer counts down twice before rebooting */
> + if (p->iTCO_version == 1)
> tmrval /= 2;
>
> /* from the specs: */
> @@ -527,7 +521,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
> * Disables TCO logic generating an SMI#
> */
> val32 = inl(SMI_EN(p));
> - val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */
> + val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */
> outl(val32, SMI_EN(p));
> }
>
>
Sigh, how broken is this architecture of the iTCO? Agreed, this leaves
no option then.
BTW, the fact that we saw an inconsistency in read-back timeout
indicates that there is still an issue for the remaining /= 2 case
(means v1), but I'm loosing interest in fixing those issues, given how
hard it is to test broadly without breaking users first.
Jan
--
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout"
2021-10-08 7:52 ` Jan Kiszka
@ 2021-10-08 13:05 ` Guenter Roeck
0 siblings, 0 replies; 5+ messages in thread
From: Guenter Roeck @ 2021-10-08 13:05 UTC (permalink / raw)
To: Jan Kiszka, Wim Van Sebroeck
Cc: linux-watchdog, linux-kernel, Mantas Mikulėnas, Javier S . Pedro
On 10/8/21 12:52 AM, Jan Kiszka wrote:
> On 08.10.21 02:33, Guenter Roeck wrote:
>> This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for
>> rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt:
>> Fix detection of SMI-off case") since those patches cause a regression
>> on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809).
>>
>> While this revert may result in some boards to only reset after twice
>> the configured timeout value, that is still better than a watchdog reset
>> after half the configured value.
>>
>> Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout")
>> Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case")
>> Cc: Jan Kiszka <jan.kiszka@siemens.com>
>> Cc: Mantas Mikulėnas <grawity@gmail.com>
>> Reported-by: Javier S. Pedro <debbugs@javispedro.com>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
>> drivers/watchdog/iTCO_wdt.c | 12 +++---------
>> 1 file changed, 3 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
>> index 643c6c2d0b72..ced2fc0deb8c 100644
>> --- a/drivers/watchdog/iTCO_wdt.c
>> +++ b/drivers/watchdog/iTCO_wdt.c
>> @@ -71,8 +71,6 @@
>> #define TCOBASE(p) ((p)->tco_res->start)
>> /* SMI Control and Enable Register */
>> #define SMI_EN(p) ((p)->smi_res->start)
>> -#define TCO_EN (1 << 13)
>> -#define GBL_SMI_EN (1 << 0)
>>
>> #define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
>> #define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
>> @@ -357,12 +355,8 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
>>
>> tmrval = seconds_to_ticks(p, t);
>>
>> - /*
>> - * If TCO SMIs are off, the timer counts down twice before rebooting.
>> - * Otherwise, the BIOS generally reboots when the SMI triggers.
>> - */
>> - if (p->smi_res &&
>> - (inl(SMI_EN(p)) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
>> + /* For TCO v1 the timer counts down twice before rebooting */
>> + if (p->iTCO_version == 1)
>> tmrval /= 2;
>>
>> /* from the specs: */
>> @@ -527,7 +521,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
>> * Disables TCO logic generating an SMI#
>> */
>> val32 = inl(SMI_EN(p));
>> - val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */
>> + val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */
>> outl(val32, SMI_EN(p));
>> }
>>
>>
>
> Sigh, how broken is this architecture of the iTCO? Agreed, this leaves
> no option then.
>
> BTW, the fact that we saw an inconsistency in read-back timeout
> indicates that there is still an issue for the remaining /= 2 case
> (means v1), but I'm loosing interest in fixing those issues, given how
> hard it is to test broadly without breaking users first.
>
Agreed. This is because the /=2 handling is only implemented in
iTCO_wdt_set_timeout() without matching code in iTCO_wdt_get_timeleft().
I don't have hardware to test, so I am not going to touch that code
myself. We can address that if/when someone reports the actual problem
and has the ability to test a fix.
Thanks,
Guenter
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout"
2021-10-08 0:33 [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout" Guenter Roeck
2021-10-08 7:52 ` Jan Kiszka
@ 2021-10-20 19:44 ` Guenter Roeck
2021-10-26 15:40 ` Wim Van Sebroeck
1 sibling, 1 reply; 5+ messages in thread
From: Guenter Roeck @ 2021-10-20 19:44 UTC (permalink / raw)
To: Wim Van Sebroeck
Cc: linux-watchdog, linux-kernel, Jan Kiszka, Mantas Mikulėnas,
Javier S . Pedro
Wim,
On Thu, Oct 07, 2021 at 05:33:02PM -0700, Guenter Roeck wrote:
> This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for
> rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt:
> Fix detection of SMI-off case") since those patches cause a regression
> on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809).
>
> While this revert may result in some boards to only reset after twice
> the configured timeout value, that is still better than a watchdog reset
> after half the configured value.
>
> Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout")
> Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case")
> Cc: Jan Kiszka <jan.kiszka@siemens.com>
> Cc: Mantas Mikulėnas <grawity@gmail.com>
> Reported-by: Javier S. Pedro <debbugs@javispedro.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Any chance you can send a pull request with this patch prior to the v5.15
release ?
Thanks,
Guenter
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout"
2021-10-20 19:44 ` Guenter Roeck
@ 2021-10-26 15:40 ` Wim Van Sebroeck
0 siblings, 0 replies; 5+ messages in thread
From: Wim Van Sebroeck @ 2021-10-26 15:40 UTC (permalink / raw)
To: Guenter Roeck
Cc: Wim Van Sebroeck, linux-watchdog, linux-kernel, Jan Kiszka,
Mantas Mikulėnas, Javier S . Pedro
Hi Guenter,
> On Thu, Oct 07, 2021 at 05:33:02PM -0700, Guenter Roeck wrote:
> > This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for
> > rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt:
> > Fix detection of SMI-off case") since those patches cause a regression
> > on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809).
> >
> > While this revert may result in some boards to only reset after twice
> > the configured timeout value, that is still better than a watchdog reset
> > after half the configured value.
> >
> > Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout")
> > Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case")
> > Cc: Jan Kiszka <jan.kiszka@siemens.com>
> > Cc: Mantas Mikulėnas <grawity@gmail.com>
> > Reported-by: Javier S. Pedro <debbugs@javispedro.com>
> > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>
> Any chance you can send a pull request with this patch prior to the v5.15
> release ?
Will do it this evening.
Kind regards,
Wim.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-10-08 0:33 [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout" Guenter Roeck
2021-10-08 7:52 ` Jan Kiszka
2021-10-08 13:05 ` Guenter Roeck
2021-10-20 19:44 ` Guenter Roeck
2021-10-26 15:40 ` Wim Van Sebroeck
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