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 > -- 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
