[Intel-gfx] [PATCH 10/11] drm/tiled: add page_flip support for multi-crtc monitors

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

This is OMG bad, but in order to get semantics that don't defeat
userspace we have to wait for both flips to complete.

So rewrite the event handling code to make sure we wait for
all crtcs in the tile group to complete flipping.

The main problem otherwise is userspace does

add_fb
ioctl(PAGE_FLIP, crtc, fb)
wait_for_event
--> page_flip event
rm_fb

This rm_fb will forcefully nuke the framebuffer from all crtcs
that are currently running, however that causes bad things to happen
like the crtc gets turned off. So we need to wait before sending
the event so userspace doesn't do this. Otherwise gnome-shell
turns off half the display after 5-10 frames.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 drivers/gpu/drm/drm_crtc.c           | 31 ++++++++++++++++++++++++++++++-
 drivers/gpu/drm/drm_irq.c            |  7 ++++++-
 drivers/gpu/drm/i915/intel_display.c | 12 ++++++++----
 include/drm/drmP.h                   |  2 ++
 4 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index e30518b..dd0649a0 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -4771,7 +4771,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 	struct drm_pending_vblank_event *e = NULL;
 	unsigned long flags;
 	int ret = -EINVAL;
-
+	int crtc_count = 1;
 	if (page_flip->flags & ~DRM_MODE_PAGE_FLIP_FLAGS ||
 	    page_flip->reserved != 0)
 		return -EINVAL;
@@ -4833,14 +4833,43 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 		e->event.base.type = DRM_EVENT_FLIP_COMPLETE;
 		e->event.base.length = sizeof e->event;
 		e->event.user_data = page_flip->user_data;
+		e->master = crtc;
 		e->base.event = &e->event.base;
 		e->base.file_priv = file_priv;
 		e->base.destroy =
 			(void (*) (struct drm_pending_event *)) kfree;
 	}
 
+	if (!list_empty(&crtc->tile_crtc_list)) {
+		struct drm_crtc *tile;
+
+		list_for_each_entry(tile, &crtc->tile_crtc_list, tile) {
+			crtc_count++;
+		}
+		if (e)
+			e->crtc_count = crtc_count;
+		list_for_each_entry(tile, &crtc->tile_crtc_list, tile) {
+			struct drm_framebuffer *tile_fb = fb;
+
+			drm_framebuffer_reference(fb);
+			old_fb = tile->primary->fb;
+
+			ret = tile->funcs->page_flip(tile, fb, e, page_flip->flags);
+			if (ret) {
+				old_fb = NULL;
+			} else {
+				tile_fb = NULL;
+			}
+			if (tile_fb)
+				drm_framebuffer_unreference(tile_fb);
+			if (old_fb)
+				drm_framebuffer_unreference(old_fb);
+		}
+	}
 	old_fb = crtc->primary->fb;
+
 	ret = crtc->funcs->page_flip(crtc, fb, e, page_flip->flags);
+
 	if (ret) {
 		if (page_flip->flags & DRM_MODE_PAGE_FLIP_EVENT) {
 			spin_lock_irqsave(&dev->event_lock, flags);
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 08ba120..9eee6e9 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -783,10 +783,15 @@ static void send_vblank_event(struct drm_device *dev,
  * Caller must hold event lock.
  */
 void drm_send_vblank_event(struct drm_device *dev, int crtc,
-		struct drm_pending_vblank_event *e)
+			   struct drm_pending_vblank_event *e)
 {
 	struct timeval now;
 	unsigned int seq;
+
+	e->crtc_count--;
+	if (e->crtc_count > 0)
+		return;
+  
 	if (crtc >= 0) {
 		seq = drm_vblank_count_and_time(dev, crtc, &now);
 	} else {
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d074d70..11a6ff3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9153,8 +9153,10 @@ static void do_intel_finish_page_flip(struct drm_device *dev,
 
 	intel_crtc->unpin_work = NULL;
 
-	if (work->event)
-		drm_send_vblank_event(dev, intel_crtc->pipe, work->event);
+	if (work->event) {
+		struct intel_crtc *tmp = to_intel_crtc(work->event->master);
+		drm_send_vblank_event(dev, tmp->pipe, work->event);
+	}
 
 	drm_crtc_vblank_put(crtc);
 
@@ -9795,8 +9797,10 @@ free_work:
 out_hang:
 		intel_crtc_wait_for_pending_flips(crtc);
 		ret = intel_pipe_set_base(crtc, crtc->x, crtc->y, fb);
-		if (ret == 0 && event)
-			drm_send_vblank_event(dev, pipe, event);
+		if (ret == 0 && event) {
+			struct intel_crtc *tmp = to_intel_crtc(event->master);
+			drm_send_vblank_event(dev, tmp->pipe, event);
+		}
 	}
 	return ret;
 }
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 1968907..c6005f6 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -982,6 +982,8 @@ struct drm_pending_vblank_event {
 	struct drm_pending_event base;
 	int pipe;
 	struct drm_event_vblank event;
+	int crtc_count;
+	struct drm_crtc *master;
 };
 
 struct drm_vblank_crtc {
-- 
1.9.3