On Tuesday 06 April 2010 00:46:11 Laurent Pinchart wrote: > On Sunday 04 April 2010 05:14:17 David Ellingsworth wrote: > > After looking at the proposed solution, I personally find the > > suggestion for a serialization flag to be quite ridiculous. As others > > have mentioned, the mere presence of the flag means that driver > > writers will gloss over any concurrency issues that might exist in > > their driver on the mere assumption that specifying the serialization > > flag will handle it all for them. > > I happen to agree with this. Proper locking is difficult, but that's not a > reason to introduce such a workaround. I'd much rather see proper > documentation for driver developers on how to implement locking properly. I've taken a different approach in another tree: http://linuxtv.org/hg/~hverkuil/v4l-dvb-ser2/ It adds two callbacks to ioctl_ops: pre_hook and post_hook. You can use these to do things like prio checking and taking your own mutex to serialize the ioctl call. This might be a good compromise between convenience and not hiding anything. Regards, Hans -- Hans Verkuil - video4linux developer - sponsored by TANDBERG -- 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
