2023-03-01 11:40:23

by Wang Wensheng

[permalink] [raw]
Subject: [PATCH -next] watchdog: sbsa: Test WDOG_HW_RUNNING bit in suspend and resume

If the sbsa_gwdt is enabled by BIOS, the kernel set WDOG_HW_RUNNING bit
and keep it alive before anyone else would open it. When system suspend,
the sbsa_gwdt would not be disabled because WDOG_ACTIVE is not set. Then
the sbsa_gwdt would reach timeout since no one touch it during system
suspend.

To solve this, just test WDOG_HW_RUNNING bit in suspend and disable the
sbsa_gwdt if the bit is set, then reopen it accordingly in resume
process.

Signed-off-by: Wang Wensheng <[email protected]>
---
drivers/watchdog/sbsa_gwdt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
index 9791c74aebd4..60875a710e43 100644
--- a/drivers/watchdog/sbsa_gwdt.c
+++ b/drivers/watchdog/sbsa_gwdt.c
@@ -360,7 +360,7 @@ static int __maybe_unused sbsa_gwdt_suspend(struct device *dev)
{
struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);

- if (watchdog_active(&gwdt->wdd))
+ if (watchdog_hw_running(&gwdt->wdd))
sbsa_gwdt_stop(&gwdt->wdd);

return 0;
@@ -371,7 +371,7 @@ static int __maybe_unused sbsa_gwdt_resume(struct device *dev)
{
struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);

- if (watchdog_active(&gwdt->wdd))
+ if (watchdog_hw_running(&gwdt->wdd))
sbsa_gwdt_start(&gwdt->wdd);

return 0;
--
2.17.1



2023-03-04 14:55:08

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH -next] watchdog: sbsa: Test WDOG_HW_RUNNING bit in suspend and resume

On 3/1/23 03:37, Wang Wensheng wrote:
> If the sbsa_gwdt is enabled by BIOS, the kernel set WDOG_HW_RUNNING bit
> and keep it alive before anyone else would open it. When system suspend,
> the sbsa_gwdt would not be disabled because WDOG_ACTIVE is not set. Then
> the sbsa_gwdt would reach timeout since no one touch it during system
> suspend.
>
> To solve this, just test WDOG_HW_RUNNING bit in suspend and disable the
> sbsa_gwdt if the bit is set, then reopen it accordingly in resume
> process.
>
> Signed-off-by: Wang Wensheng <[email protected]>
> ---
> drivers/watchdog/sbsa_gwdt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
> index 9791c74aebd4..60875a710e43 100644
> --- a/drivers/watchdog/sbsa_gwdt.c
> +++ b/drivers/watchdog/sbsa_gwdt.c
> @@ -360,7 +360,7 @@ static int __maybe_unused sbsa_gwdt_suspend(struct device *dev)
> {
> struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>
> - if (watchdog_active(&gwdt->wdd))
> + if (watchdog_hw_running(&gwdt->wdd))
> sbsa_gwdt_stop(&gwdt->wdd);

That will not stop the watchdog if it is currently open (active)
and if it wasn't running when the module was loaded.

Guenter

>
> return 0;
> @@ -371,7 +371,7 @@ static int __maybe_unused sbsa_gwdt_resume(struct device *dev)
> {
> struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>
> - if (watchdog_active(&gwdt->wdd))
> + if (watchdog_hw_running(&gwdt->wdd))
> sbsa_gwdt_start(&gwdt->wdd);
>
> return 0;


2023-03-04 16:17:13

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH -next] watchdog: sbsa: Test WDOG_HW_RUNNING bit in suspend and resume

On 3/4/23 06:54, Guenter Roeck wrote:
> On 3/1/23 03:37, Wang Wensheng wrote:
>> If the sbsa_gwdt is enabled by BIOS, the kernel set WDOG_HW_RUNNING bit
>> and keep it alive before anyone else would open it. When system suspend,
>> the sbsa_gwdt would not be disabled because WDOG_ACTIVE is not set. Then
>> the sbsa_gwdt would reach timeout since no one touch it during system
>> suspend.
>>
>> To solve this, just test WDOG_HW_RUNNING bit in suspend and disable the
>> sbsa_gwdt if the bit is set, then reopen it accordingly in resume
>> process.
>>
>> Signed-off-by: Wang Wensheng <[email protected]>
>> ---
>>   drivers/watchdog/sbsa_gwdt.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
>> index 9791c74aebd4..60875a710e43 100644
>> --- a/drivers/watchdog/sbsa_gwdt.c
>> +++ b/drivers/watchdog/sbsa_gwdt.c
>> @@ -360,7 +360,7 @@ static int __maybe_unused sbsa_gwdt_suspend(struct device *dev)
>>   {
>>       struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>> -    if (watchdog_active(&gwdt->wdd))
>> +    if (watchdog_hw_running(&gwdt->wdd))
>>           sbsa_gwdt_stop(&gwdt->wdd);
>
> That will not stop the watchdog if it is currently open (active)
> and if it wasn't running when the module was loaded.
>

I just sent a patch which fixes the problem in the watchdog core.

Guenter

> Guenter
>
>>       return 0;
>> @@ -371,7 +371,7 @@ static int __maybe_unused sbsa_gwdt_resume(struct device *dev)
>>   {
>>       struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>> -    if (watchdog_active(&gwdt->wdd))
>> +    if (watchdog_hw_running(&gwdt->wdd))
>>           sbsa_gwdt_start(&gwdt->wdd);
>>       return 0;
>


2023-03-04 16:24:19

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH -next] watchdog: sbsa: Test WDOG_HW_RUNNING bit in suspend and resume

On 3/1/23 03:37, Wang Wensheng wrote:
> If the sbsa_gwdt is enabled by BIOS, the kernel set WDOG_HW_RUNNING bit
> and keep it alive before anyone else would open it. When system suspend,
> the sbsa_gwdt would not be disabled because WDOG_ACTIVE is not set. Then
> the sbsa_gwdt would reach timeout since no one touch it during system
> suspend.
>
> To solve this, just test WDOG_HW_RUNNING bit in suspend and disable the
> sbsa_gwdt if the bit is set, then reopen it accordingly in resume
> process.
>
> Signed-off-by: Wang Wensheng <[email protected]>

Reviewed-by: Guenter Roeck <[email protected]>

Prerequisite: "watchdog: core: Always set WDOG_HW_RUNNING when starting watchdog"

Guenter

> ---
> drivers/watchdog/sbsa_gwdt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
> index 9791c74aebd4..60875a710e43 100644
> --- a/drivers/watchdog/sbsa_gwdt.c
> +++ b/drivers/watchdog/sbsa_gwdt.c
> @@ -360,7 +360,7 @@ static int __maybe_unused sbsa_gwdt_suspend(struct device *dev)
> {
> struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>
> - if (watchdog_active(&gwdt->wdd))
> + if (watchdog_hw_running(&gwdt->wdd))
> sbsa_gwdt_stop(&gwdt->wdd);
>
> return 0;
> @@ -371,7 +371,7 @@ static int __maybe_unused sbsa_gwdt_resume(struct device *dev)
> {
> struct sbsa_gwdt *gwdt = dev_get_drvdata(dev);
>
> - if (watchdog_active(&gwdt->wdd))
> + if (watchdog_hw_running(&gwdt->wdd))
> sbsa_gwdt_start(&gwdt->wdd);
>
> return 0;