ADHOC/replicant-frameworks_native
3
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Fix potential deadlock in stopPreview/stopRecord.

Browse Source 
Some camera HALs spin up a preview thread and need to wait for
the thread to exit. This can create a potential deadlock. In
stopPreview, we take the main lock. If a preview callback occurs
while the lock is held, the preview thread will block. If the
camera HAL is waiting for the preview thread to exit, this will
cause a deadlock.

This patch breaks out the preview buffer heap into a separate
mutex. This mutex is never held when the main lock is held, thus
preventing the deadlock from occuring.
This commit is contained in:
Dave Sparks 2009-11-10 17:08:08 -08:00
parent 3bde289d23
commit ff0f38e6fe
2 changed files with 46 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

71
camera/libcameraservice/CameraService.cpp
View File

@ -683,22 +683,30 @@ void CameraService::Client::stopPreview()
{
LOGD("stopPreview (pid %d)", getCallingPid());
Mutex::Autolock lock(mLock);
if (checkPid() != NO_ERROR) return;
// hold main lock during state transition
{
Mutex::Autolock lock(mLock);
if (checkPid() != NO_ERROR) return;
if (mHardware == 0) {
LOGE("mHardware is NULL, returning.");
return;
if (mHardware == 0) {
LOGE("mHardware is NULL, returning.");
return;
}
mHardware->stopPreview();
mHardware->disableMsgType(CAMERA_MSG_PREVIEW_FRAME);
LOGD("stopPreview(), hardware stopped OK");
if (mSurface != 0 && !mUseOverlay) {
mSurface->unregisterBuffers();
}
}
mHardware->stopPreview();
mHardware->disableMsgType(CAMERA_MSG_PREVIEW_FRAME);
LOGD("stopPreview(), hardware stopped OK");
if (mSurface != 0 && !mUseOverlay) {
mSurface->unregisterBuffers();
// hold preview buffer lock
{
Mutex::Autolock lock(mPreviewLock);
mPreviewBuffer.clear();
}
mPreviewBuffer.clear();
}
// stop recording mode
@ -706,24 +714,31 @@ void CameraService::Client::stopRecording()
{
LOGD("stopRecording (pid %d)", getCallingPid());
Mutex::Autolock lock(mLock);
if (checkPid() != NO_ERROR) return;
// hold main lock during state transition
{
Mutex::Autolock lock(mLock);
if (checkPid() != NO_ERROR) return;
if (mHardware == 0) {
LOGE("mHardware is NULL, returning.");
return;
if (mHardware == 0) {
LOGE("mHardware is NULL, returning.");
return;
}
if (mMediaPlayerBeep.get() != NULL) {
mMediaPlayerBeep->seekTo(0);
mMediaPlayerBeep->start();
}
mHardware->stopRecording();
mHardware->disableMsgType(CAMERA_MSG_VIDEO_FRAME);
LOGD("stopRecording(), hardware stopped OK");
}
if (mMediaPlayerBeep.get() != NULL) {
mMediaPlayerBeep->seekTo(0);
mMediaPlayerBeep->start();
// hold preview buffer lock
{
Mutex::Autolock lock(mPreviewLock);
mPreviewBuffer.clear();
}
mHardware->stopRecording();
mHardware->disableMsgType(CAMERA_MSG_VIDEO_FRAME);
LOGD("stopRecording(), hardware stopped OK");
mPreviewBuffer.clear();
}
// release a recording frame
@ -1216,10 +1231,10 @@ void CameraService::Client::copyFrameAndPostCopiedFrame(const sp<ICameraClient>&
// provided it's big enough. Don't allocate the memory or
// perform the copy if there's no callback.
// hold the lock while we grab a reference to the preview buffer
// hold the preview lock while we grab a reference to the preview buffer
sp<MemoryHeapBase> previewBuffer;
{
Mutex::Autolock lock(mLock);
Mutex::Autolock lock(mPreviewLock);
if (mPreviewBuffer == 0) {
mPreviewBuffer = new MemoryHeapBase(size, 0, NULL);
} else if (size > mPreviewBuffer->virtualSize()) {

4
camera/libcameraservice/CameraService.h
View File

@ -181,7 +181,6 @@ private:
mutable Condition mReady;
sp<CameraService> mCameraService;
sp<ISurface> mSurface;
sp<MemoryHeapBase> mPreviewBuffer;
int mPreviewCallbackFlag;
sp<MediaPlayer> mMediaPlayerClick;
@ -197,6 +196,9 @@ private:
sp<OverlayRef> mOverlayRef;
int mOverlayW;
int mOverlayH;
mutable Mutex mPreviewLock;
sp<MemoryHeapBase> mPreviewBuffer;
};
// ----------------------------------------------------------------------------