Hi Hans,
On Tue, Sep 06, 2011 at 01:20:26PM +0200, Hans Verkuil wrote:
> On Tuesday, September 06, 2011 13:07:42 Sakari Ailus wrote:
> > Hi,
> >
> > I remember being in a discussion a while ago regarding the requirement of
> > having all the controls belonging to the same class in
> > VIDIOC_{TRY,S,G}_EXT_CTRLS. The answer I remember was that there was a
> > historical reason for this and it no longer exists.
>
> The original rule was that all controls have to belong to the same class. This was
> done to simplify drivers. Drivers that use the control framework can handle a class
> of 0, which means that the controls can be of any class.
>
> But we still have drivers that implement S_EXT_CTRLS but do not use the control
> framework, and for those this restriction is still valid. Usually such drivers will only
> handle MPEG class controls through that API.
>
> So I don't think this restriction can be lifted as long as there are drivers that do not
> use the control framework.
All the drivers which implement *_EXT_CTRLS and check for ctrl_class do the
check for a single class. All the references for ctrl_class in individual
drivers (which actually were only checks that the user has set the field
correctly) are removed by the patch I posted.
So I don't see a reason why we couldn't just say "please set this to zero
from now on".
--
Sakari Ailus
e-mail: sakari.ailus@xxxxxx jabber/XMPP/Gmail: sailus@xxxxxxxxxxxxxx
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