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?
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