On Mon, 2010-03-01 at 10:58 +0100, Hans Verkuil wrote: > > Hello Laurent, > > > > On Mon, Mar 1, 2010 at 3:57 AM, Laurent Pinchart > > <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > >> I don't think it should matter which API (the base one or the extended > >> one) > >> you use for controls, be they private, standard or whatever. I don't see > >> a > >> reason for disallowing some controls to be used through one or the other > >> API. > > > > I would generally agree. My original belief was that the extended > > control API was designed to be a superset of the older API and that it > > could be used for both types of controls. Imagine my surprise to find > > that private controls were specifically excluded from the extended > > control interface. > > New private controls should not use V4L2_CID_PRIVATE_BASE at all. That > mechanism was a really bad idea. Instead a new control should be added to > the appropriate control class and with a offset >= 0x1000. See for example > the CX2341X private controls in videodev2.h. I recall doing something like this a while ago: #define CX18_AV_CID_USER_PRIV_BASE (V4L2_CTRL_CLASS_USER | 0x1000) #define CX18_AV_CID_EXTRA_12DB_GAIN (CX18_AV_CID_USER_PRIV_BASE+0) ..... http://linuxtv.org/hg/~awalls/v4l-dvb-ctls/file/e4b2c5d550b5/linux/drivers/media/video/cx18/cx18-av-core.h#l77 (I'm not sure if it's a good example though.) I'm still just waiting for an approved method for implementing such video decoder controls. I don't care how, just that there is a way. I don't have much in the way of plans to offer, because I really don't grok all the existing issues with controls. Regards, Andy > The EXT_G/S_CTRLS ioctls do not accept PRIVATE_BASE because I want to > force driver developers to stop using PRIVATE_BASE. So only G/S_CTRL will > support controls in that range for backwards compatibility. > > Regards, > > Hans -- 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
