From ed55cb5a228c7ca5544f41da8897420104764555 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stephan=20A=C3=9Fmus?= <superstippi@gmx.de>
Date: Sat, 23 Oct 2010 22:19:43 +0000
Subject: [PATCH] Cache the retrace semaphore. Use the right kind of locking in
 the method that needs it.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39096 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../app/drawing/AccelerantHWInterface.cpp     | 25 ++++++++++---------
 .../app/drawing/AccelerantHWInterface.h       |  2 ++
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/servers/app/drawing/AccelerantHWInterface.cpp b/src/servers/app/drawing/AccelerantHWInterface.cpp
index 57ee1d4329..d4ffb4a794 100644
--- a/src/servers/app/drawing/AccelerantHWInterface.cpp
+++ b/src/servers/app/drawing/AccelerantHWInterface.cpp
@@ -138,6 +138,8 @@ AccelerantHWInterface::AccelerantHWInterface()
 
 	fInitialModeSwitch(true),
 
+	fRetraceSemaphore(-1),
+
 	fRectParams(new (nothrow) fill_rect_params[kDefaultParamsCount]),
 	fRectParamsCount(kDefaultParamsCount),
 	fBlitParams(new (nothrow) blit_params[kDefaultParamsCount]),
@@ -1017,30 +1019,29 @@ AccelerantHWInterface::GetMonitorInfo(monitor_info* info)
 sem_id
 AccelerantHWInterface::RetraceSemaphore()
 {
+	AutoWriteLocker _(this);
+
+	if (fRetraceSemaphore != -1)
+		return fRetraceSemaphore;
+
 	accelerant_retrace_semaphore AccelerantRetraceSemaphore =
 		(accelerant_retrace_semaphore)fAccelerantHook(
 			B_ACCELERANT_RETRACE_SEMAPHORE, NULL);
 	if (!AccelerantRetraceSemaphore)
-		return B_UNSUPPORTED;
+		fRetraceSemaphore = B_UNSUPPORTED;
+	else
+		fRetraceSemaphore = AccelerantRetraceSemaphore();
 
-	return AccelerantRetraceSemaphore();
+	return fRetraceSemaphore;
 }
 
 
 status_t
 AccelerantHWInterface::WaitForRetrace(bigtime_t timeout)
 {
-	AutoReadLocker _(this);
-
-	accelerant_retrace_semaphore AccelerantRetraceSemaphore
-		= (accelerant_retrace_semaphore)fAccelerantHook(
-			B_ACCELERANT_RETRACE_SEMAPHORE, NULL);
-	if (!AccelerantRetraceSemaphore)
-		return B_UNSUPPORTED;
-
-	sem_id sem = AccelerantRetraceSemaphore();
+	sem_id sem = RetraceSemaphore();
 	if (sem < 0)
-		return B_ERROR;
+		return sem;
 
 	return acquire_sem_etc(sem, 1, B_RELATIVE_TIMEOUT, timeout);
 }
diff --git a/src/servers/app/drawing/AccelerantHWInterface.h b/src/servers/app/drawing/AccelerantHWInterface.h
index 02ed61a95c..fd81fd2782 100644
--- a/src/servers/app/drawing/AccelerantHWInterface.h
+++ b/src/servers/app/drawing/AccelerantHWInterface.h
@@ -177,6 +177,8 @@ private:
 			display_mode		fDisplayMode;
 			bool				fInitialModeSwitch;
 
+			sem_id				fRetraceSemaphore;
+
 	mutable	fill_rect_params*	fRectParams;
 	mutable	uint32				fRectParamsCount;
 	mutable	blit_params*		fBlitParams;