drm/atomic-helper: Export framebuffer_changed()

BugLink: http://bugs.launchpad.net/bugs/1546572
The Rockchip driver cannot use drm_atomic_helper_wait_for_vblanks()
because it has hardware counters for neither vblanks nor scanlines.

In order to simplify re-implementing the functionality for this driver,
export the framebuffer_changed() helper so it can be reused.

Signed-off-by: John Keeping <john@metanate.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit c240906d36653944d5c049df7ce667a7e8bea6ac)
Signed-off-by: Alberto Milone <alberto.milone@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 042598ae12fcdf1b3f6b50e3cd4c85ba2bbd249d..8a3f96c1b1d83bd26195ce595b0aaeec457c5877 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -956,9 +956,23 @@ static void wait_for_fences(struct drm_device *dev,
        }
 }
 
-static bool framebuffer_changed(struct drm_device *dev,
-                               struct drm_atomic_state *old_state,
-                               struct drm_crtc *crtc)
+/**
+ * drm_atomic_helper_framebuffer_changed - check if framebuffer has changed
+ * @dev: DRM device
+ * @old_state: atomic state object with old state structures
+ * @crtc: DRM crtc
+ *
+ * Checks whether the framebuffer used for this CRTC changes as a result of
+ * the atomic update.  This is useful for drivers which cannot use
+ * drm_atomic_helper_wait_for_vblanks() and need to reimplement its
+ * functionality.
+ *
+ * Returns:
+ * true if the framebuffer changed.
+ */
+bool drm_atomic_helper_framebuffer_changed(struct drm_device *dev,
+                                          struct drm_atomic_state *old_state,
+                                          struct drm_crtc *crtc)
 {
        struct drm_plane *plane;
        struct drm_plane_state *old_plane_state;
@@ -975,6 +989,7 @@ static bool framebuffer_changed(struct drm_device *dev,
 
        return false;
 }
+EXPORT_SYMBOL(drm_atomic_helper_framebuffer_changed);
 
 /**
  * drm_atomic_helper_wait_for_vblanks - wait for vblank on crtcs
@@ -1009,7 +1024,8 @@ drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
                if (old_state->legacy_cursor_update)
                        continue;
 
-               if (!framebuffer_changed(dev, old_state, crtc))
+               if (!drm_atomic_helper_framebuffer_changed(dev,
+                               old_state, crtc))
                        continue;
 
                ret = drm_crtc_vblank_get(crtc);

diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 8cba54a2a0a0f78a198ba9ae82a96f6b3f6631f8..186adfbb9f2e1e05336bc65255e18ffe55e46e7d 100644 (file)
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -42,6 +42,10 @@ int drm_atomic_helper_commit(struct drm_device *dev,
                             struct drm_atomic_state *state,
                             bool async);
 
+bool drm_atomic_helper_framebuffer_changed(struct drm_device *dev,
+                                          struct drm_atomic_state *old_state,
+                                          struct drm_crtc *crtc);
+
 void drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
                                        struct drm_atomic_state *old_state);