Hi Pawel, On Tuesday 05 April 2011 17:12:29 Pawel Osciak wrote: > On Mon, Apr 4, 2011 at 03:27, Laurent Pinchart wrote: > > On Monday 04 April 2011 01:51:05 Pawel Osciak wrote: > >> Hi, > >> > >> This series implements a slight redesign of the stop_streaming() > >> callback in vb2. The callback has been made obligatory. The drivers are > >> expected to finish all hardware operations and cede ownership of all > >> buffers before returning, but are not required to call > >> vb2_buffer_done() for any of them. The return value from this callback > >> has also been removed. > > > > What's the rationale behind this patch set ? I've always been against vb2 > > controlling the stream state (vb2 should handle buffer management only in > > my opinion) and I'd like to understand why you want to make it required. > > I might have overstated the intention saying it was a 'redesign'. It > actually doesn't change the overall stop_streaming callback idea, I am > just simplifying it with this patch, while also emphasizing its role > by making it obligatory. Drivers were always required to finish > everything they were doing with the buffers before returning from > stop_streaming. But until now, stop_streaming was expecting the driver > to call vb2_buffer_done for all buffers it received via buf_queue. > We've decided it's superfluous, so I am removing this requirement. > Also, I didn't see any use for the return value from stop_streaming so > I removed it as well. Apart from the above, nothing has really > changed. Does that mean that drivers don't have to implement the stop_streaming callback if they finish all buffer-related operations before calling vb2 functions that stop streaming ? > > I plan to use vb2 in the uvcvideo driver (when vb2 will provide a way to > > handle device disconnection), and uvcvideo will stop the stream before > > calling vb2_queue_release() and vb2_streamoff(). Would will I need a > > stop_stream operation ? > > I actually just yesterday noticed your response from a couple of weeks ago > to my comments to your original buf_queue proposal in my ever growing pile > of mail, sorry about that, I will reply to that as soon as I have time to > properly read it and think about it. Nevertheless, I have the same question > as Marek here, would there be anything preventing you from doing that in > stop_streaming? See my reply to Marek :-) -- 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
