[RFC 6/6] drm/fence: support fence_collection on atomic commit

[Gustavo Padovan]

From: Gustavo Padovan <gustavo.pado...@collabora.co.uk>

Let atomic_commit() wait on a collection of fences before proceed with
the scanout.

Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
---
 drivers/gpu/drm/drm_atomic.c        | 9 +++++++++
 drivers/gpu/drm/drm_atomic_helper.c | 9 +++++----
 include/drm/drm_crtc.h              | 2 +-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 8bc364c..28a65d1 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -29,6 +29,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_plane_helper.h>
+#include <linux/sync_file.h>

 /**
  * drm_atomic_state_default_release -
@@ -795,6 +796,14 @@ static int drm_atomic_plane_check(struct drm_plane *plane,
                return -EINVAL;
        }

+#ifdef CONFIG_SYNC_FILE
+       if (state->fence_fd >= 0) {
+               state->fences = sync_file_fences_get(state->fence_fd);
+               if (!state->fences)
+                       return -EINVAL;
+       }
+#endif
+
        return 0;
 }

diff --git a/drivers/gpu/drm/drm_atomic_helper.c 
b/drivers/gpu/drm/drm_atomic_helper.c
index 4f91f84..a6e34b6 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -977,14 +977,12 @@ static void wait_for_fences(struct drm_device *dev,
        int i;

        for_each_plane_in_state(state, plane, plane_state, i) {
-               if (!plane->state->fence)
+               if (!plane->state->fences)
                        continue;

                WARN_ON(!plane->state->fb);

-               fence_wait(plane->state->fence, false);
-               fence_put(plane->state->fence);
-               plane->state->fence = NULL;
+               fence_collection_wait(plane->state->fences);
        }
 }

@@ -2654,6 +2652,9 @@ void __drm_atomic_helper_plane_destroy_state(struct 
drm_plane *plane,
 {
        if (state->fb)
                drm_framebuffer_unreference(state->fb);
+
+       if (state->fences)
+               fence_collection_put(state->fences);
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index a8f6ec0..c221c28 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1257,7 +1257,7 @@ struct drm_plane_state {

        struct drm_crtc *crtc;   /* do not write directly, use 
drm_atomic_set_crtc_for_plane() */
        struct drm_framebuffer *fb;  /* do not write directly, use 
drm_atomic_set_fb_for_plane() */
-       struct fence *fence;
+       struct fence_collection *fences;
        int fence_fd;

        /* Signed dest location allows it to be partially off screen */
-- 
2.5.0