[PATCHv2 42/45] drm: omapdrm: add omap_atomic_wait_for_gos()

[Tomi Valkeinen]

omap_atomic_complete() uses drm_atomic_helper_wait_for_vblanks() to wait
for all operations to finish. That works, but can easily cause waits for
vblanks when no wait is actually necessary.

This patch adds omap_atomic_wait_for_gos() and uses it instead.
omap_atomic_wait_for_gos() waits for the GO bit to get unset for all
relevant crtcs.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
---
 drivers/gpu/drm/omapdrm/omap_crtc.c |  7 +++++++
 drivers/gpu/drm/omapdrm/omap_drv.c  | 31 ++++++++++++++++++++++++++++++-
 drivers/gpu/drm/omapdrm/omap_drv.h  |  1 +
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
index 2c0d91a67418..8f905d2c8074 100644
--- a/drivers/gpu/drm/omapdrm/omap_crtc.c
+++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
@@ -80,6 +80,13 @@ enum omap_channel omap_crtc_channel(struct drm_crtc *crtc)
 	return omap_crtc->channel;
 }
 
+bool omap_crtc_needs_wait(struct drm_crtc *crtc)
+{
+	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
+
+	return dispc_mgr_go_busy(omap_crtc->channel);
+}
+
 /* -----------------------------------------------------------------------------
  * DSS Manager Functions
  */
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index 50f555530e55..c03405593f9f 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -66,6 +66,35 @@ struct omap_atomic_state_commit {
 	u32 crtcs;
 };
 
+static void omap_atomic_wait_for_gos(struct drm_device *dev,
+					 struct drm_atomic_state *old_state)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *old_crtc_state;
+	int i, ret;
+
+	for_each_crtc_in_state(old_state, crtc, old_crtc_state, i) {
+		if (!crtc->state->enable)
+			continue;
+
+		if (!omap_crtc_needs_wait(crtc))
+			continue;
+
+		ret = drm_crtc_vblank_get(crtc);
+		if (ret != 0)
+			continue;
+
+		ret = wait_event_timeout(dev->vblank[i].queue,
+					 !omap_crtc_needs_wait(crtc),
+					 msecs_to_jiffies(50));
+		if (!ret)
+			dev_warn(dev->dev,
+				 "atomic flush timeout (pipe %u)!\n", i);
+
+		drm_crtc_vblank_put(crtc);
+	}
+}
+
 static void omap_atomic_complete(struct omap_atomic_state_commit *commit)
 {
 	struct drm_device *dev = commit->dev;
@@ -79,7 +108,7 @@ static void omap_atomic_complete(struct omap_atomic_state_commit *commit)
 	drm_atomic_helper_commit_planes(dev, old_state);
 	drm_atomic_helper_commit_modeset_enables(dev, old_state);
 
-	drm_atomic_helper_wait_for_vblanks(dev, old_state);
+	omap_atomic_wait_for_gos(dev, old_state);
 
 	drm_atomic_helper_cleanup_planes(dev, old_state);
 
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.h b/drivers/gpu/drm/omapdrm/omap_drv.h
index 0b7a055bf007..27bbf7c4d76e 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.h
+++ b/drivers/gpu/drm/omapdrm/omap_drv.h
@@ -147,6 +147,7 @@ void omap_crtc_pre_init(void);
 void omap_crtc_pre_uninit(void);
 struct drm_crtc *omap_crtc_init(struct drm_device *dev,
 		struct drm_plane *plane, enum omap_channel channel, int id);
+bool omap_crtc_needs_wait(struct drm_crtc *crtc);
 
 struct drm_plane *omap_plane_init(struct drm_device *dev,
 		int id, enum drm_plane_type type);
-- 
2.1.4