Re: [PATCH 2/2] drm/amdgpu: add AMDGPURESET uevent on AMD GPU reset

["Somalapuram, Amaranath" <asomalap@amd.com>]

Hi Christian,

if sending udev event during reset is going to create problem, we can 
move this code from reset sequence to re-int  (after GPU reset succeeded).

Regards,

S.Amarnath

On 1/17/2022 5:27 PM, Christian König wrote:
> Am 17.01.22 um 12:43 schrieb Sharma, Shashank:
>> Hello Christian,
>>
>> On 1/17/2022 11:37 AM, Christian König wrote:
>>> Am 17.01.22 um 11:34 schrieb Somalapuram, Amaranath:
>>>> [SNIP]
>>>> Any suggestion how we can notify user space during this situation. 
>>>
>>> Well trace points should work. They use a ring buffer and are 
>>> specially made to work in such situations.
>>
>> We are anyways sending a trace event with data, but can trace event 
>> be a wake up source for an application (like a tracer) ? This DRM 
>> event is just to indicate that reset happened, so app has to read 
>> from trace file.
>
> Yeah, that's a really good question I can't fully answer. As far as I 
> know you can filter in userspace what you get from the tracer, but I 
> don't know if you can block on a specific event.
>
> Christian.
>
>>
>>>
>>> Alternative would be to audit the udev code and allow giving a GFP 
>>> mask to the function to make sure that we don't run into the deadlock.
>>>
>>> Another alternative is a debugfs file which just blocks for the next 
>>> reset to happen.
>>>
>>
>> - Shashank
>>
>>> Regards,
>>> Christian.
>>>
>>>> Regards,
>>>>
>>>> S.Amarnath
>>>>
>>>
>