On Fri March 15 2013 14:58:35 Mauro Carvalho Chehab wrote:
> Em Fri, 15 Mar 2013 11:27:23 +0100
> Hans Verkuil <hverk...@xs4all.nl> escreveu:
>
> > From: Hans Verkuil <hans.verk...@cisco.com>
> >
> > This ioctl is defined as IOW, so pass the argument by value instead of by
> > reference. I could have chosen to add const instead, but this is 1) easier
> > to handle in drivers and 2) consistent with the s_std subdev operation.
>
> Hmm... this could potentially break userspace. I remember I saw in the past
> some code that used the returned standard. I can't remember where. It could
> be inside the V4L1 compat layer, but I think it was on some userspace app(s).
>
> Had you verify how the several different userspace apps handle S_STD?
video_usercopy doesn't call copy_to_user for write-only ioctls, so any changed
data will never make it to userspace.
If there is an app that expects to see the returned standard then they broke
many years ago :-)
Regards,
Hans
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