[PATCH v4 1/3] drm: Introduce device wedged event

[Asahi Lina]

On 9/8/24 12:07 AM, Lucas De Marchi wrote:
> On Sat, Sep 07, 2024 at 08:38:30PM GMT, Asahi Lina wrote:
>>
>>
>> On 9/6/24 6:42 PM, Raag Jadav wrote:
>>> Introduce device wedged event, which will notify userspace of wedged
>>> (hanged/unusable) state of the DRM device through a uevent. This is
>>> useful especially in cases where the device is in unrecoverable state
>>> and requires userspace intervention for recovery.
>>>
>>> Purpose of this implementation is to be vendor agnostic. Userspace
>>> consumers (sysadmin) can define udev rules to parse this event and
>>> take respective action to recover the device.
>>>
>>> Consumer expectations:
>>> ----------------------
>>> 1) Unbind driver
>>> 2) Reset bus device
>>> 3) Re-bind driver
>>
>> Is this supposed to be normative? For drm/asahi we have a "wedged"
>> concept (firmware crashed), but the only possible recovery action is a
>> full system reboot (which might still be desirable to allow userspace to
>> trigger automatically in some scenarios) since there is no bus-level
>> reset and no firmware reload possible.
> 
> maybe let drivers hint possible/supported recovery mechanisms and then
> sysadmin chooses what to do?

How would we do this? A textual value for the event or something like
that? ("WEDGED=bus-reset" vs "WEDGED=reboot"?)

~~ Lina