[PATCH v3 11/12] drm/virtio: implement context init: add virtio_gpu_fence_event

[Greg KH]

On Tue, Sep 21, 2021 at 04:20:23PM -0700, Gurchetan Singh wrote:
> Similar to DRM_VMW_EVENT_FENCE_SIGNALED.  Sends a pollable event
> to the DRM file descriptor when a fence on a specific ring is
> signaled.
> 
> One difference is the event is not exposed via the UAPI -- this is
> because host responses are on a shared memory buffer of type
> BLOB_MEM_GUEST [this is the common way to receive responses with
> virtgpu].  As such, there is no context specific read(..)
> implementation either -- just a poll(..) implementation.
> 
> Signed-off-by: Gurchetan Singh <gurchetansingh at chromium.org>
> Acked-by: Nicholas Verne <nverne at chromium.org>
> ---
>  drivers/gpu/drm/virtio/virtgpu_drv.c   | 43 +++++++++++++++++++++++++-
>  drivers/gpu/drm/virtio/virtgpu_drv.h   |  7 +++++
>  drivers/gpu/drm/virtio/virtgpu_fence.c | 10 ++++++
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c | 34 ++++++++++++++++++++
>  4 files changed, 93 insertions(+), 1 deletion(-)

This commit seems to cause a crash in a virtual drm gpu driver for
Android.  I have reverted this, and the next commit in the series from
Linus's tree and all is good again.

Any ideas?

thanks,

greg k-h