On Thu, Apr 2, 2009 at 11:29 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: [...] >> So, questions are: >> >> 1) What for is lock/unlock_kernel() used in open? > > It's pointless. Just remove it. Actually, i can see lock/unlock_kernel() in open in other V4L drivers too. What for is it used in other drivers? >> 2) Can it be replaced by mutex, for example? > > No need. Good, so we can remove it. >> Please, comments, explanations are more than welcome. > > But what is really wrong is the way the 'users' field is used: that should > be an atomic counter: on the first-time-open you set up the device, and > when the last user goes away you can close it down. > > Currently if you open the device a second time and then close that second > fh, the first gets muted by that close. Not what you want! > > Actually, I don't see why this stuff is in the open/close at all, unless > this saves some measurable amount of power consumption. I'd just move the > setup code in the open() to the probe() and after that both the open() and > close() functions become no-ops. > > Regards, > > Hans > > -- > Hans Verkuil - video4linux developer - sponsored by TANDBERG Agreed, thanks for explanations and suggestions. -- Best regards, Klimov Alexey -- 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
