Re: [PATCH v2 1/2] drm: Add GPU reset sysfs event

[Pekka Paalanen <ppaalanen@gmail.com>]

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On Thu, 10 Mar 2022 11:56:41 -0800
Rob Clark <robdclark@gmail.com> wrote:

> For something like just notifying a compositor that a gpu crash
> happened, perhaps drm_event is more suitable.  See
> virtio_gpu_fence_event_create() for an example of adding new event
> types.  Although maybe you want it to be an event which is not device
> specific.  This isn't so much of a debugging use-case as simply
> notification.

Hi,

for this particular use case, are we now talking about the display
device (KMS) crashing or the rendering device (OpenGL/Vulkan) crashing?

If the former, I wasn't aware that display device crashes are a thing.
How should a userspace display server react to those?

If the latter, don't we have EGL extensions or Vulkan API already to
deliver that?

The above would be about device crashes that directly affect the
display server. Is that the use case in mind here, or is it instead
about notifying the display server that some application has caused a
driver/hardware crash? If the latter, how should a display server react
to that? Disconnect the application?

Shashank, what is the actual use case you are developing this for?

I've read all the emails here so far, and I don't recall seeing it
explained.

Btw. somewhat relatedly, there has been work aiming to allow
graceful hot-unplug of DRM devices. There is a kernel doc outlining how
the various APIs should react towards userspace when a DRM device
suddenly disappears. That seems to have some overlap here IMO.

See https://www.kernel.org/doc/html/latest/gpu/drm-uapi.html#device-hot-unplug
which also has a couple pointers to EGL and Vulkan APIs.


Thanks,
pq

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