On Thursday 23 December 2010 09:34:27 Laurent Pinchart wrote: > Hi Mauro, > > On Tuesday 21 December 2010 12:10:18 Mauro Carvalho Chehab wrote: > > You didn't understand me: uvcvideo is returning -EBUSY to format changes > > with buffers freed. > > As explained in my answer to Hans, that's on purpose. > > The uvcvideo driver releases buffers when calling REQBUFS(0). However, the > file handle is still marked as owning the device for streaming purpose, so > other applications can't change the format or request buffers. > > The reason for that is to avoid race conditions when an application wants > to change the resolution during capture. As the application has to stop > capture, call REQBUFS(0), change the format, request buffers and restart > capture, it prevents another application from racing it after REQBUFS(0). And it's actually not correct. I've just tested the latest uvcvideo version, and I can start capture in a second application after calling REQBUFS(0) in the first one. > As Hans correctly pointed out, this should be implemented using the > priority ioctls. I will fix that. -- 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
