[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 at vger.kernel.org # v4.0+
> Cc: Michael Ellerman <mpe at ellerman.id.au>
> Signed-off-by: Vasant Hegde <hegdevasant at 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:
>