[v2,0/2] drm/virtio: fence handling in case of multi scanouts

Message

Kim, Dongwon June 3, 2022, 9:18 p.m. UTC

Current primary plane update flow when blob is enabled (for zero copy
display sharing) shows fence synchronization problems when multi planes
are referencing a same single large FB (i.e. multi displays in extended
mode). This is because there is only one fence bound to the FB and this
single fence is re-used asynchronously when flushing all associated
planes.

The way to prevent this is to assign the fence for each plane so that
flushing one plane won't be affecting or affected by other plane's flush
operation.

The 1st patch "drm/virtio: .release ops for virtgpu fence release" which
adds device specific release ops is for making the virtio_gpu fence freed
upon the last dma_fence_put call.

The 2nd patch "drm/virtio: fence created per cursor/plane update" contains
the main implementation of per-plane fence.

Dongwon Kim (2):
  drm/virtio: .release ops for virtgpu fence release
  drm/virtio: fence created per cursor/plane update

 drivers/gpu/drm/virtio/virtgpu_drv.h   |   1 -
 drivers/gpu/drm/virtio/virtgpu_fence.c |   8 ++
 drivers/gpu/drm/virtio/virtgpu_plane.c | 103 ++++++++++---------------
 3 files changed, 47 insertions(+), 65 deletions(-)