[PATCH] powerpc/rtas: Introduce rtas_get_sensor_nonblocking() for pci hotplug driver.

[Nathan Lynch]

Mahesh J Salgaonkar <mahesh at linux.ibm.com> writes:
> On 2021-11-29 22:53:41 Mon, Nathan Lynch wrote:
>> Mahesh Salgaonkar <mahesh at linux.ibm.com> writes:
>> >
>> > However on certain PHB failures, the rtas call get-sesnor-state() returns
>> > extended busy error (9902) until PHB is recovered by phyp. Once PHB is
>> > recovered, the get-sensor-state() returns success with correct presence
>> > status. The rtas call interface rtas_get_sensor() loops over the rtas call
>> > on extended delay return code (9902) until the return value is either
>> > success (0) or error (-1). This causes the EEH handler to get stuck for ~6
>> > seconds before it could notify that the pci error has been detected and
>> > stop any active operations.
>> 
>> I am curious whether you see any difference with "powerpc/rtas:
>> rtas_busy_delay() improvements" which was recently applied. It will
>> cause the the calling task to sleep in response to a 990x status instead
>> of immediately retrying:
>> 
>> https://git.kernel.org/powerpc/c/38f7b7067dae0c101be573106018e8af22a90fdf
>> 
>> If that commit helps then maybe this change isn't needed.
>
> I tried with above commit but it didn't help.

OK, not too surprising, but thank you for checking.