On (21/03/24 11:14), Tomasz Figa wrote:
> > > > +static int uvc_ioctl_s_roi(struct file *file, void *fh,
> > > > + struct v4l2_selection *sel)
> > > > +{
> > > > + struct uvc_fh *handle = fh;
> > > > + struct uvc_streaming *stream = handle->stream;
> > > > + struct uvc_roi_rect *roi;
> > > > + int ret;
> > > > +
> > > > + if (!validate_roi_bounds(stream, sel))
> > > > + return -E2BIG;
> > >
> > > Not sure if this is the correct approach or if we should convert the
> > > value to the closest valid...
> >
> > Well, at this point we know that ROI rectangle dimensions are out of
> > sane value range. I'd rather tell user-space about integer overflow.
>
> Adjusting the rectangle to something supported by the hardware is
> mentioned explicitly in the V4L2 API documentation and is what drivers
> have to implement. Returning an error on invalid value is not a
> correct behavior here (and similarly for many other operations, e.g.
> S_FMT).
Well, in this particular case we are talking about user-space that wants
to set ROI rectangle that is knowingly violates device's GET_MAX and
overflows UVC ROI rectangle u16 value range. That's a clear bug in user-space.
Do we want to pretend that user-space does the correct thing and fixup
stuff behind the scenes?
> > Looking for the closest ROI rectangle that suffice can be rather
> > tricky. It may sounds like we can just use BOUNDARIES_MAX, but this
> > is what Firmware D returns for GET_MAX
> >
> > ioctl(V4L2_SEL_TGT_ROI_BOUNDS_MAX)
> >
> > 0, 0, 65535, 65535
>
> Perhaps the frame size would be the correct bounds?
I can check that.
