Hello Hans, Sakari and Laurent: I am back from holidays :). Shall I prepare a new patchset with the suggestion from Hans? Thanks! On Mon, Jul 20, 2015 at 4:31 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > On 07/20/2015 03:52 PM, Ricardo Ribalda Delgado wrote: >> Hello >> >> I have no preference over the two implementations, but I see an issue >> with this suggestion. >> >> >> What happens to out out tree drivers, or drivers that don't support >> this functionality? >> >> With the ioctl, the user receives a -ENOTTY. So he knows there is >> something wrong with the driver. >> >> With this class, the driver might interpret this a simple G_VAL and >> return he current value with no way for the user to know what is going >> on. > > Drivers that implement the current API correctly will return an error > if V4L2_CTRL_WHICH_DEF_VAL was specified. Such drivers will interpret > the value as a control class, and no control classes in that range exist. > See also class_check() in v4l2-ctrls.c. > > The exception here is uvc which doesn't have this class check and it will > just return the current value :-( > > I don't see a way around this, unfortunately. > > Out-of-tree drivers that use the control framework are fine, and I don't > really care about drivers (out-of-tree or otherwise) that do not use the > control framework. > >> Regarding the new implementation.... I can make some code next week, >> this week I am 120% busy :) > > Wait until there is a decision first :-) > > It's not a lot of work, I think. > > Regards, > > Hans > >> What do you think? >> -- >> 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 >> > -- Ricardo Ribalda -- 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
