Re: [PATCH v4 3/4] drm/virtio: add in/out fence support for explicit synchronization

On Fri, Nov 09, 2018 at 06:13:52PM +0100, Robert Foss wrote:

Hey Gerd,

On 2018-11-09 11:13, Gerd Hoffmann wrote:

quoted

On Mon, Nov 05, 2018 at 05:25:05PM +0000, Emil Velikov wrote:

quoted

On Mon, 5 Nov 2018 at 11:42, Robert Foss [off-list ref] wrote:

quoted

When the execbuf call receives an in-fence it will get the dma_fence
related to that fence fd and wait on it before submitting the draw call.

On the out-fence side we get fence returned by the submitted draw call
and attach it to a sync_file and send the sync_file fd to userspace. On
error -1 is returned to userspace.

Signed-off-by: Gustavo Padovan <redacted>
Signed-off-by: Robert Foss <redacted>
Suggested-by: Rob Herring <robh@kernel.org>
Reviewed-by: Emil Velikov <redacted>
---

Changes since v3:
  - Move all in_fence handling to the same VIRTGPU_EXECBUF_FENCE_FD_IN block

Fwiw my suggestion was to explicitly document whether the IOCTL can
support, simultaneously, IN and OUT fence.

Yes, that would be good.  Code looks like it is supposed to work, but
explicitly saying so in the commit message would be nice.

On it! Will send out a v5.

quoted

Also: should we use separate fields for in/out fds?

I'm not sure I understand which fields you're referring to.

fence_in_fd & fence_out_fd in the ioctl struct (patch #2).

cheers,
  Gerd