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, Hans On 11/29/2013 10:58 AM, 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 final 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. > > Regards, > > Hans > > -- > 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 > -- 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
