[PATCH] powerpc/pseries: Do not initiate shutdown when system is running on UPS

[PATCH] powerpc/pseries: Do not initiate shutdown when system is running on UPS

[Vasant Hegde]

As per PAPR specification whenever system is running on UPS we have to
wait for predefined time (default 10mins) before initiating shutdown.

We have user space tool (rtas_errd) to monitor for EPOW events and
initiate shutdown after predefined time. Hence do not initiate shutdown
whenever we get EPOW_SHUTDOWN_ON_UPS event.

Fixes: 79872e35 (powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown)
Cc: stable@vger.kernel.org # v4.0+
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/pseries/ras.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index f3736fcd98fc..13c86a292c6d 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -184,7 +184,6 @@ static void handle_system_shutdown(char event_modifier)
 	case EPOW_SHUTDOWN_ON_UPS:
 		pr_emerg("Loss of system power detected. System is running on"
 			 " UPS/battery. Check RTAS error log for details\n");
-		orderly_poweroff(true);
 		break;
 
 	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
-- 
2.26.2

Re: [PATCH] powerpc/pseries: Do not initiate shutdown when system is running on UPS

[Tyrel Datwyler]

On 8/18/20 3:54 AM, Vasant Hegde wrote:
> As per PAPR specification whenever system is running on UPS we have to
> wait for predefined time (default 10mins) before initiating shutdown.

The wording in PAPR seems a little unclear. It states for an
EPOW_SYSTEM_SHUTDOWN action code that an EPOW error should be logged followed by
scheduling a shutdown to begin after an OS defined delay interval (with 10
minutes the suggested default).

However, the modifier code descriptions seems to imply that a normal shutdown is
the only one that should happen with no additional delay.

For EPOW sensor value = 3 (EPOW_SYSTEM_SHUTDOWN)
0x01 = Normal system shutdown with no additional delay
0x02 = Loss of utility power, system is running on UPS/Battery
0x03 = Loss of system critical functions, system should be shutdown
0x04 = Ambient temperature too high

For 0x03-0x04 we also do an orderly_poweroff().

Not sure if it really matters, but I was curious and this is just what I gleaned
from glancing at PAPR.

-Tyrel

> 
> We have user space tool (rtas_errd) to monitor for EPOW events and
> initiate shutdown after predefined time. Hence do not initiate shutdown
> whenever we get EPOW_SHUTDOWN_ON_UPS event.
> 
> Fixes: 79872e35 (powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown)
> Cc: stable@vger.kernel.org # v4.0+
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
> ---
>  arch/powerpc/platforms/pseries/ras.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
> index f3736fcd98fc..13c86a292c6d 100644
> --- a/arch/powerpc/platforms/pseries/ras.c
> +++ b/arch/powerpc/platforms/pseries/ras.c
> @@ -184,7 +184,6 @@ static void handle_system_shutdown(char event_modifier)
>  	case EPOW_SHUTDOWN_ON_UPS:
>  		pr_emerg("Loss of system power detected. System is running on"
>  			 " UPS/battery. Check RTAS error log for details\n");
> -		orderly_poweroff(true);
>  		break;
> 
>  	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
> 

Re: [PATCH] powerpc/pseries: Do not initiate shutdown when system is running on UPS

[Vasant Hegde]

On 8/19/20 1:05 AM, Tyrel Datwyler wrote:
> On 8/18/20 3:54 AM, Vasant Hegde wrote:
>> As per PAPR specification whenever system is running on UPS we have to
>> wait for predefined time (default 10mins) before initiating shutdown.
> 
> The wording in PAPR seems a little unclear. It states for an
> EPOW_SYSTEM_SHUTDOWN action code that an EPOW error should be logged followed by
> scheduling a shutdown to begin after an OS defined delay interval (with 10
> minutes the suggested default).
> 
> However, the modifier code descriptions seems to imply that a normal shutdown is
> the only one that should happen with no additional delay.
> 
> For EPOW sensor value = 3 (EPOW_SYSTEM_SHUTDOWN)
> 0x01 = Normal system shutdown with no additional delay
> 0x02 = Loss of utility power, system is running on UPS/Battery
> 0x03 = Loss of system critical functions, system should be shutdown
> 0x04 = Ambient temperature too high
> 
> For 0x03-0x04 we also do an orderly_poweroff().
> 
> Not sure if it really matters, but I was curious and this is just what I gleaned
> from glancing at PAPR.

Correct. PAPR is bit confusing. But we know for sure that when running on UPS we 
don't need to shutdown immediately.

For values 0x03 and 0x04 I think its ok to initiate shutdown (that's the same 
behaviour exists for long time). I can double check with firmware folks.

-Vasant

> 
> -Tyrel
> 
>>
>> We have user space tool (rtas_errd) to monitor for EPOW events and
>> initiate shutdown after predefined time. Hence do not initiate shutdown
>> whenever we get EPOW_SHUTDOWN_ON_UPS event.
>>
>> Fixes: 79872e35 (powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown)
>> Cc: stable@vger.kernel.org # v4.0+
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
>> ---
>>   arch/powerpc/platforms/pseries/ras.c | 1 -
>>   1 file changed, 1 deletion(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
>> index f3736fcd98fc..13c86a292c6d 100644
>> --- a/arch/powerpc/platforms/pseries/ras.c
>> +++ b/arch/powerpc/platforms/pseries/ras.c
>> @@ -184,7 +184,6 @@ static void handle_system_shutdown(char event_modifier)
>>   	case EPOW_SHUTDOWN_ON_UPS:
>>   		pr_emerg("Loss of system power detected. System is running on"
>>   			 " UPS/battery. Check RTAS error log for details\n");
>> -		orderly_poweroff(true);
>>   		break;
>>
>>   	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
>>
> 

Re: [PATCH] powerpc/pseries: Do not initiate shutdown when system is running on UPS

[Sasha Levin]

Hi

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag
fixing commit: 79872e35469b ("powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown").

The bot has tested the following trees: v5.8.2, v5.7.16, v5.4.59, v4.19.140, v4.14.193, v4.9.232, v4.4.232.

v5.8.2: Build OK!
v5.7.16: Build OK!
v5.4.59: Build OK!
v4.19.140: Build OK!
v4.14.193: Build OK!
v4.9.232: Build OK!
v4.4.232: Failed to apply! Possible dependencies:
    b4af279a7cba ("powerpc/pseries: Limit EPOW reset event warnings")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

-- 
Thanks
Sasha