Hi Guennadi, On Friday 20 July 2012 11:55:31 Guennadi Liakhovetski wrote: > On Thu, 28 Jun 2012, Hans Verkuil wrote: > > Hi all, > > > > This is the third version of this patch series. > > > > The first version is here: > > > > http://www.mail-archive.com/linux-media@xxxxxxxxxxxxxxx/msg47558.html > > Nice to see an owner concept added to the vb2. In soc-camera we're also > using a concept of a "streamer" user. This is the user, that first calls > one of data-flow related ioctl()s, like s_fmt(), streamon(), streamoff() > and all buffer queue-related operations. I realise that this your > patch-set only deals with the buffer queue, but in principle, do you think > it would make sense to use such a concept globally? We probably don't want > to let other processes mess with any of the above calls as long as one > process is actively managing the streaming. I think that's a good idea (the uvcvideo driver implements something similar), but I'm not sure whether the spec currently describes the expected behaviour and relationships between ioctls correctly. That could be a topic for the V4L2 ambiguities discussions during KS. Such a a mechanism should not be imposed on drivers though, as it probably wouldn't cover all use cases (think about mem-to-mem drivers where the format is per file-handle for instance). -- 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
