Hi Hans, Thank you for the patches. For patches 1, 2, 4, 7 and 10, Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> On Thursday 05 December 2013 09:21:39 Hans Verkuil wrote: > This patch series does some cleanups in the qbuf/prepare_buf handling > (the first two patches). The third patch removes the 'fileio = NULL' > hack. That hack no longer works when dealing with asynchronous calls > from a kernel thread so it had to be fixed. > > The next three patches implement retrying start_streaming() if there are > not enough buffers queued for the DMA engine to start. I know that there > are more drivers that can be simplified with this feature available in > the core. Those drivers do the retry of start_streaming in the buf_queue > op which frankly defeats the purpose of having a central start_streaming > op. But I leave it to the driver developers to decide whether or not to > cleanup their drivers. > > The big advantage is that apps can just call STREAMON first, then start > queuing buffers without having to know the minimum number of buffers that > have to be queued before the DMA engine will kick in. It always annoyed > me that vb2 didn't take care of that for me as it is easy enough to do. > > The next two patches add vb2 thread support which is necessary > for both videobuf2-dvb (the vb2 replacement of videobuf-dvb) and for e.g. > alsa drivers where you use the same trick as with dvb. > > The thread implementation has been tested with both alsa recording and > playback for an internal driver (sorry, I can't share the source yet). > > The next patch adds a fix based on a patch from Andy that removes the > file I/O emulation assumption that buffers are dequeued in the same > order that they were enqueued. > > The final patch fixes another race condition between QBUF/PREPARE_BUF > and REQBUFS in the USERPTR case, also caused by the fact that __prepare_buf > temporarily unlocks the queue lock. The race was found by Laurent. > > Regards, > > Hans > > New in v3: > > - Added a comment to the thread_start function making it explicit that > it is for use with videobuf2-dvb only. > - Added patch 10/10 to address yet another race condition. > > New in v2: > > - Added a PREPARING state in patch 1 to prevent a race condition that > Laurent mentioned (two QBUF calls with the same index number at the same > time). - Changed some minor issues in patch 4 that Laurent mentioned in his > review. - Added the reworked version of Andy's original patch to remove the > order assumption in the file I/O emulation. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
