[PATCH 2/2] present: Fix presentation of flips out of order

[Chris Wilson]

The flip queue currently only holds events submitted to the driver for
flipping, awaiting the completion notifier. It is short. We therefore
can speed up interrupt processing by keeping the small number of events
ready to be flipped on the end of the flip queue. By appending the
events to the flip_queue in the order that they become ready, we also
resolve one issue causing Present to display frames out of order.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 present/present.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/present/present.c b/present/present.c
index b132f4d..bce41f4 100644
--- a/present/present.c
+++ b/present/present.c
@@ -327,10 +327,10 @@ present_re_execute(present_vblank_ptr vblank)
 static void
 present_flip_try_ready(ScreenPtr screen)
 {
-    present_vblank_ptr  vblank, tmp;
+    present_vblank_ptr  vblank;
 
-    xorg_list_for_each_entry_safe(vblank, tmp, &present_exec_queue, event_queue) {
-        if (vblank->flip_ready) {
+    xorg_list_for_each_entry(vblank, &present_flip_queue, event_queue) {
+        if (vblank->queued) {
             present_re_execute(vblank);
             return;
         }
@@ -623,6 +623,8 @@ present_execute(present_vblank_ptr vblank, uint64_t ust, uint64_t crtc_msc)
             DebugPresent(("\tr %lld %p (pending %p unflip %lld)\n",
                           vblank->event_id, vblank,
                           screen_priv->flip_pending, screen_priv->unflip_event_id));
+            xorg_list_del(&vblank->event_queue);
+            xorg_list_append(&vblank->event_queue, &present_flip_queue);
             vblank->flip_ready = TRUE;
             return;
         }
@@ -938,6 +940,7 @@ present_abort_vblank(ScreenPtr screen, RRCrtcPtr crtc, uint64_t event_id, uint64
     xorg_list_for_each_entry(vblank, &present_flip_queue, event_queue) {
         if (vblank->event_id == event_id) {
             xorg_list_del(&vblank->event_queue);
+            vblank->queued = FALSE;
             return;
         }
     }
-- 
2.1.4