Don't wait for vsync for late frames

If multiple frames are ready to be displayed, then block only on the last one. This condition happens rarely in practice, usually when there is a high spike of CPU activity. This change may prevent unnecessary frame drops.
grate-driver · Jul 12, 2020 · 1b31790 · 1b31790
1 parent ee7032a
commit 1b31790
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Showing 3 changed files with 26 additions and 12 deletions.
diff --git a/src/presentation_queue.c b/src/presentation_queue.c
@@ -23,7 +23,7 @@ static void * presentation_queue_thr(void *opaque)
 {
     tegra_pq *pq = opaque;
     tegra_pqt *pqt = pq->pqt;
-    tegra_surface *surf, *tmp, *next;
+    tegra_surface *disp_surf, *surf, *tmp, *next;
     VdpTime earliest_time = UINT64_MAX;
     VdpTime time = UINT64_MAX;
     struct timespec tp;
@@ -70,6 +70,8 @@ static void * presentation_queue_thr(void *opaque)
         }
 
         earliest_time = UINT64_MAX;
+        disp_surf = NULL;
+        next = NULL;
 
         LIST_FOR_EACH_ENTRY_SAFE(surf, tmp, &pq->surf_list, list_item) {
             pthread_mutex_lock(&surf->lock);
@@ -95,13 +97,23 @@ static void * presentation_queue_thr(void *opaque)
 
             DebugMsg("displaying surface %u\n", surf->surface_id);
 
-            pqt_display_surface(pqt, surf, true, false);
+            if (disp_surf) {
+                pqt_display_surface(pqt, disp_surf, true, false, false);
+            }
+
+            disp_surf = surf;
+        }
+
+        if (disp_surf) {
+            pqt_display_surface(pqt, disp_surf, true, false, true);
         }
 
         time = earliest_time;
 
         if (time != UINT64_MAX) {
-            pqt_prepare_dri_surface(pqt, next);
+            if (next) {
+                pqt_prepare_dri_surface(pqt, next);
+            }
 
             DebugMsg("next wake on %llu\n", time);
         } else {
@@ -356,7 +368,7 @@ VdpStatus vdp_presentation_queue_display(
     surf->disp_height = clip_height ?: surf->height;
 
     if (earliest_presentation_time == 0 || !_Xglobal_lock) {
-        pqt_display_surface(pq->pqt, surf, true, false);
+        pqt_display_surface(pq->pqt, surf, true, false, true);
         goto unlock_surf;
     }
 

diff --git a/src/presentation_queue_target.c b/src/presentation_queue_target.c
@@ -196,7 +196,7 @@ static bool initialize_dri2(tegra_pqt *pqt)
     return dev->dri2_ready;
 }
 
-static void pqt_display_dri(tegra_pqt *pqt, tegra_surface *surf)
+static void pqt_display_dri(tegra_pqt *pqt, tegra_surface *surf, bool vsync)
 {
     tegra_device *dev = pqt->dev;
     CARD64 ust, msc, sbc;
@@ -206,7 +206,9 @@ static void pqt_display_dri(tegra_pqt *pqt, tegra_surface *surf)
 
     DRI2GetMSC(dev->display, pqt->drawable, &ust, &msc, &sbc);
     DRI2SwapBuffers(dev->display, pqt->drawable, msc + 1, 0, 0, &count);
-    DRI2WaitMSC(dev->display, pqt->drawable, msc + 1, 0, 0, &ust, &msc, &sbc);
+    if (vsync) {
+        DRI2WaitMSC(dev->display, pqt->drawable, msc + 1, 0, 0, &ust, &msc, &sbc);
+    }
 
     if (pqt->dri_prep_surf == surf) {
         pqt->dri_prep_surf = NULL;
@@ -598,7 +600,7 @@ void pqt_prepare_dri_surface(tegra_pqt *pqt, tegra_surface *surf)
 }
 
 void pqt_display_surface(tegra_pqt *pqt, tegra_surface *surf,
-                         bool update_status, bool transit)
+                         bool update_status, bool transit, bool vsync)
 {
     tegra_device *dev = pqt->dev;
 
@@ -618,13 +620,13 @@ void pqt_display_surface(tegra_pqt *pqt, tegra_surface *surf,
         dev->dri2_ready)
     {
         pqt_update_dri_buffer(pqt, surf);
-        pqt_display_dri(pqt, surf);
+        pqt_display_dri(pqt, surf, vsync);
 
         if (transit || pqt->disp_state != TEGRA_PQT_DRI) {
             transit_display_to_dri(pqt);
         }
     } else {
-        pqt_display_xv(pqt, surf, update_status);
+        pqt_display_xv(pqt, surf, vsync);
 
         if (transit || pqt->disp_state != TEGRA_PQT_XV) {
             transit_display_to_xv(pqt);
@@ -671,14 +673,14 @@ static void * pqt_display_thr(void *opaque)
             pqt->overlapped_current = overlapped;
 
             if (pqt->disp_surf) {
-                pqt_display_surface(pqt, pqt->disp_surf, false, true);
+                pqt_display_surface(pqt, pqt->disp_surf, false, true, false);
             }
         }
         if (pqt->win_move) {
             pqt->win_move = false;
 
             if (pqt->disp_surf) {
-                pqt_display_surface(pqt, pqt->disp_surf, false, false);
+                pqt_display_surface(pqt, pqt->disp_surf, false, false, false);
             }
         }
         pthread_mutex_unlock(&pqt->lock);

diff --git a/src/vdpau_tegra.h b/src/vdpau_tegra.h
@@ -417,7 +417,7 @@ void set_presentation_queue_target(VdpPresentationQueueTarget target,
                                    tegra_pqt *pqt);
 void pqt_display_surface_to_idle_state(tegra_pqt *pqt);
 void pqt_display_surface(tegra_pqt *pqt, tegra_surface *surf,
-                         bool update_status, bool transit);
+                         bool update_status, bool transit, bool vsync);
 void pqt_prepare_dri_surface(tegra_pqt *pqt, tegra_surface *surf);
 
 tegra_pq * __get_presentation_queue(VdpPresentationQueue presentation_queue);