frontends: va: fix vaQuerySurfaceStatus and vaSyncSurface for decode

Use the new get_decoder_fence vfunc to  implement
vaQuerySurfaceStatus and vaSyncSurface in the va state tracker.

A pointer to the surface's fence is passed to the codecs before the
end_frame vfunc and the codec is responsible for allocating a fence on
command stream submission.

This fence is then queried on vaQuerySurfaceStatus and waited on in
vaSyncSurface.

Notably both functions were not implemented as per the VA-API docs for
PIPE_VIDEO_ENTRYPOINT_BITSTREAM.

Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Sil Vilerino <sivileri@microsoft.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Reviewed-by: Boyuan Zhang <Boyuan.Zhang@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20133>

src/gallium/frontends/va/picture.c

@@ -1024,6 +1024,8 @@ vlVaEndPicture(VADriverContextP ctx, VAContextID context_id)
       surf->feedback = feedback;
       surf->coded_buf = coded_buf;
       coded_buf->associated_encode_input_surf = context->target_id;
+   } else if (context->decoder->entrypoint == PIPE_VIDEO_ENTRYPOINT_BITSTREAM) {
+      context->desc.base.fence = &surf->fence;
    }
 
    context->decoder->end_frame(context->decoder, context->target, &context->desc.base);

src/gallium/frontends/va/surface.c

@@ -114,8 +114,14 @@ vlVaSyncSurface(VADriverContextP ctx, VASurfaceID render_target)
       return VA_STATUS_ERROR_INVALID_SURFACE;
    }
 
-   if (!surf->feedback) {
-      // No outstanding operation: nothing to do.
+   /* This is checked before getting the context below as
+    * surf->ctx is only set in begin_frame
+    * and not when the surface is created
+    * Some apps try to sync/map the surface right after creation and
+    * would get VA_STATUS_ERROR_INVALID_CONTEXT
+    */
+   if ((!surf->feedback) && (!surf->fence)) {
+      // No outstanding encode/decode operation: nothing to do.
       mtx_unlock(&drv->mutex);
       return VA_STATUS_SUCCESS;
    }
@@ -126,7 +132,18 @@ vlVaSyncSurface(VADriverContextP ctx, VASurfaceID render_target)
       return VA_STATUS_ERROR_INVALID_CONTEXT;
    }
 
-   if (context->decoder->entrypoint == PIPE_VIDEO_ENTRYPOINT_ENCODE) {
+   if (context->decoder->entrypoint == PIPE_VIDEO_ENTRYPOINT_BITSTREAM) {
+      int ret = 0;
+
+      if (context->decoder->get_decoder_fence)
+         ret = context->decoder->get_decoder_fence(context->decoder,
+                                                   surf->fence,
+                                                   PIPE_DEFAULT_DECODER_FEEDBACK_TIMEOUT_NS);
+
+      mtx_unlock(&drv->mutex);
+      // Assume that the GPU has hung otherwise.
+      return ret ? VA_STATUS_SUCCESS : VA_STATUS_ERROR_TIMEDOUT;
+   } else if (context->decoder->entrypoint == PIPE_VIDEO_ENTRYPOINT_ENCODE) {
       if (!drv->pipe->screen->get_video_param(drv->pipe->screen,
                               context->decoder->profile,
                               context->decoder->entrypoint,
@@ -176,6 +193,19 @@ vlVaQuerySurfaceStatus(VADriverContextP ctx, VASurfaceID render_target, VASurfac
       return VA_STATUS_ERROR_INVALID_SURFACE;
    }
 
+   /* This is checked before getting the context below as
+    * surf->ctx is only set in begin_frame
+    * and not when the surface is created
+    * Some apps try to sync/map the surface right after creation and
+    * would get VA_STATUS_ERROR_INVALID_CONTEXT
+    */
+   if ((!surf->feedback) && (!surf->fence)) {
+      // No outstanding encode/decode operation: nothing to do.
+      *status = VASurfaceReady;
+      mtx_unlock(&drv->mutex);
+      return VA_STATUS_SUCCESS;
+   }
+
    context = handle_table_get(drv->htab, surf->ctx);
    if (!context) {
       mtx_unlock(&drv->mutex);
@@ -187,6 +217,25 @@ vlVaQuerySurfaceStatus(VADriverContextP ctx, VASurfaceID render_target, VASurfac
          *status=VASurfaceReady;
       else
          *status=VASurfaceRendering;
+   } else if (context->decoder->entrypoint == PIPE_VIDEO_ENTRYPOINT_BITSTREAM) {
+      int ret = 0;
+
+      if (context->decoder->get_decoder_fence)
+         ret = context->decoder->get_decoder_fence(context->decoder,
+                                                   surf->fence, 0);
+
+      if (ret)
+         *status = VASurfaceReady;
+      else
+      /* An approach could be to just tell the client that this is not
+       * implemented, but this breaks other code.  Compromise by at least
+       * conservatively setting the status to VASurfaceRendering if we can't
+       * query the hardware.  Note that we _must_ set the status here, otherwise
+       * it comes out of the function unchanged. As we are returning
+       * VA_STATUS_SUCCESS, the client would be within his/her rights to use a
+       * potentially uninitialized/invalid status value unknowingly.
+       */
+         *status = VASurfaceRendering;
    }
 
    mtx_unlock(&drv->mutex);

src/gallium/frontends/va/va_private.h

@@ -374,6 +374,7 @@ typedef struct {
    bool force_flushed;
    struct pipe_video_buffer *obsolete_buf;
    enum pipe_format encoder_format;
+   struct pipe_fence_handle *fence;
 } vlVaSurface;
 
 typedef struct {