drm/sti: do not post GDP command if no update

Do not process update requests with unmodified parameters.

This typically happens when the driver is called with legacy
(non-atomic) IOCTL : in that case atomic_update() is called multiple
times with the same parameters.

Signed-off-by: Vincent Abriou <vincent.abriou@st.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sti/sti_gdp.c b/drivers/gpu/drm/sti/sti_gdp.c
index 7f6d0790cca6..86279f5022c2 100644
--- a/drivers/gpu/drm/sti/sti_gdp.c
+++ b/drivers/gpu/drm/sti/sti_gdp.c
@@ -708,6 +708,21 @@ static void sti_gdp_atomic_update(struct drm_plane *drm_plane,
         if (!crtc || !fb)
                 return;
 
+        if ((oldstate->fb == state->fb) &&
+            (oldstate->crtc_x == state->crtc_x) &&
+            (oldstate->crtc_y == state->crtc_y) &&
+            (oldstate->crtc_w == state->crtc_w) &&
+            (oldstate->crtc_h == state->crtc_h) &&
+            (oldstate->src_x == state->src_x) &&
+            (oldstate->src_y == state->src_y) &&
+            (oldstate->src_w == state->src_w) &&
+            (oldstate->src_h == state->src_h)) {
+                /* No change since last update, do not post cmd */
+                DRM_DEBUG_DRIVER("No change, not posting cmd\n");
+                plane->status = STI_PLANE_UPDATED;
+                return;
+        }
+
         if (!gdp->vtg) {
                 struct sti_compositor *compo = dev_get_drvdata(gdp->dev);
                 struct sti_mixer *mixer = to_sti_mixer(crtc);