drm/xen: Explicitly disable automatic sending of vblank event

[linux-2.6-microblaze.git] / drivers / gpu / drm / xen / xen_drm_front_kms.c

diff --git a/drivers/gpu/drm/xen/xen_drm_front_kms.c b/drivers/gpu/drm/xen/xen_drm_front_kms.c
index 4f34c52..78096bb 100644 (file)
--- a/drivers/gpu/drm/xen/xen_drm_front_kms.c
+++ b/drivers/gpu/drm/xen/xen_drm_front_kms.c
@@ -220,6 +220,24 @@ static bool display_send_page_flip(struct drm_simple_display_pipe *pipe,
        return false;
 }
 
+static int display_check(struct drm_simple_display_pipe *pipe,
+                        struct drm_plane_state *plane_state,
+                        struct drm_crtc_state *crtc_state)
+{
+       /*
+        * Xen doesn't initialize vblanking via drm_vblank_init(), so
+        * DRM helpers assume that it doesn't handle vblanking and start
+        * sending out fake VBLANK events automatically.
+        *
+        * As xen contains it's own logic for sending out VBLANK events
+        * in send_pending_event(), disable no_vblank (i.e., the xen
+        * driver has vblanking support).
+        */
+       crtc_state->no_vblank = false;
+
+       return 0;
+}
+
 static void display_update(struct drm_simple_display_pipe *pipe,
                           struct drm_plane_state *old_plane_state)
 {
@@ -284,6 +302,7 @@ static const struct drm_simple_display_pipe_funcs display_funcs = {
        .enable = display_enable,
        .disable = display_disable,
        .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
+       .check = display_check,
        .update = display_update,
 };