[vlc-commits] Revert "video_output:control: merge the two wait conditions"

[Steve Lhomme]

vlc | branch: master | Steve Lhomme <robux4 at ycbcr.xyz> | Wed Jan 20 12:26:48 2021 +0100| [872b90865add883675b37c31d3e10ac4986900bf] | committer: Steve Lhomme

Revert "video_output:control: merge the two wait conditions"

This reverts commit 6d31fe007b20dbe07eba5420de8ec84653c7c7c9.

The waiting and signaling of the same condition variable in the same thread
seems to be a no-no. And because of this commit some playback tests failed
as well as tsan checks.

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=872b90865add883675b37c31d3e10ac4986900bf
---

 src/video_output/control.c | 25 +++++++++++--------------
 src/video_output/control.h |  4 +++-
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/src/video_output/control.c b/src/video_output/control.c
index eb6fea7681..5d72caf60e 100644
--- a/src/video_output/control.c
+++ b/src/video_output/control.c
@@ -33,9 +33,11 @@
 void vout_control_Init(vout_control_t *ctrl)
 {
     vlc_mutex_init(&ctrl->lock);
+    vlc_cond_init(&ctrl->wait_request);
     vlc_cond_init(&ctrl->wait_available);
 
     ctrl->is_held = false;
+    ctrl->is_waiting = false;
     ctrl->forced_awake = false;
     ARRAY_INIT(ctrl->cmd);
 }
@@ -50,7 +52,7 @@ void vout_control_PushMouse(vout_control_t *ctrl, const vlc_mouse_t *video_mouse
 {
     vlc_mutex_lock(&ctrl->lock);
     ARRAY_APPEND(ctrl->cmd, *video_mouse);
-    vlc_cond_signal(&ctrl->wait_available);
+    vlc_cond_signal(&ctrl->wait_request);
     vlc_mutex_unlock(&ctrl->lock);
 }
 
@@ -58,14 +60,14 @@ void vout_control_Wake(vout_control_t *ctrl)
 {
     vlc_mutex_lock(&ctrl->lock);
     ctrl->forced_awake = true;
-    vlc_cond_signal(&ctrl->wait_available);
+    vlc_cond_signal(&ctrl->wait_request);
     vlc_mutex_unlock(&ctrl->lock);
 }
 
 void vout_control_Hold(vout_control_t *ctrl)
 {
     vlc_mutex_lock(&ctrl->lock);
-    while (ctrl->is_held)
+    while (ctrl->is_held || !ctrl->is_waiting)
         vlc_cond_wait(&ctrl->wait_available, &ctrl->lock);
     ctrl->is_held = true;
     vlc_mutex_unlock(&ctrl->lock);
@@ -85,24 +87,19 @@ int vout_control_Pop(vout_control_t *ctrl, vlc_mouse_t *mouse, vlc_tick_t deadli
     bool has_cmd = false;
     vlc_mutex_lock(&ctrl->lock);
 
-    while (ctrl->is_held)
-        // wait until code outside the vout thread loop has finished doing things
-        vlc_cond_wait(&ctrl->wait_available, &ctrl->lock);
-
     if (ctrl->cmd.i_size <= 0) {
         /* Spurious wakeups are perfectly fine */
         if (deadline != VLC_TICK_INVALID && !ctrl->forced_awake) {
-            ctrl->is_held = true;
-            // wait for something to happen while blocking vout_control_Hold
-            // - new mouse state received
-            // - control_Wake called: new picture arrived or terminating vout
-            vlc_cond_timedwait(&ctrl->wait_available, &ctrl->lock, deadline);
-            // allow vout_control_Hold again
-            ctrl->is_held = false;
+            ctrl->is_waiting = true;
             vlc_cond_signal(&ctrl->wait_available);
+            vlc_cond_timedwait(&ctrl->wait_request, &ctrl->lock, deadline);
+            ctrl->is_waiting = false;
         }
     }
 
+    while (ctrl->is_held)
+        vlc_cond_wait(&ctrl->wait_available, &ctrl->lock);
+
     if (ctrl->cmd.i_size > 0) {
         has_cmd = true;
         *mouse = ARRAY_VAL(ctrl->cmd, 0);
diff --git a/src/video_output/control.h b/src/video_output/control.h
index ce46454ebe..e85af59236 100644
--- a/src/video_output/control.h
+++ b/src/video_output/control.h
@@ -28,11 +28,13 @@
 /* */
 typedef struct {
     vlc_mutex_t lock;
+    vlc_cond_t  wait_request;
     vlc_cond_t  wait_available;
 
     /* */
     bool forced_awake;
-    bool is_held; // control FIFO held outside of the vout thread
+    bool is_waiting;
+    bool is_held;
     DECL_ARRAY(vlc_mouse_t) cmd;
 } vout_control_t;