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SubjectRe: [PATCH v5 00/39] i.MX Media Driver
On Mon, Mar 20, 2017 at 05:29:07PM +0100, Philipp Zabel wrote:
> According to the documentation [1], you are doing the right thing:
>
> The struct v4l2_subdev_frame_interval pad references a non-existing
> pad, or the pad doesn’t support frame intervals.
>
> But v4l2_subdev_call returns -ENOIOCTLCMD if the g_frame_interval op is
> not implemented at all, which is turned into -ENOTTY by video_usercopy.
>
> [1] https://linuxtv.org/downloads/v4l-dvb-apis/uapi/v4l/vidioc-subdev-g-frame-interval.html#return-value

Thanks for confirming.

> > Maybe something like the following would be a better idea?
> >
> > utils/media-ctl/media-ctl.c | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/utils/media-ctl/media-ctl.c b/utils/media-ctl/media-ctl.c
> > index f61963a..a50a559 100644
> > --- a/utils/media-ctl/media-ctl.c
> > +++ b/utils/media-ctl/media-ctl.c
> > @@ -81,22 +81,22 @@ static void v4l2_subdev_print_format(struct media_entity *entity,
> > struct v4l2_mbus_framefmt format;
> > struct v4l2_fract interval = { 0, 0 };
> > struct v4l2_rect rect;
> > - int ret;
> > + int ret, err_fi;
> >
> > ret = v4l2_subdev_get_format(entity, &format, pad, which);
> > if (ret != 0)
> > return;
> >
> > - ret = v4l2_subdev_get_frame_interval(entity, &interval, pad);
> > - if (ret != 0 && ret != -ENOTTY)
> > - return;
> > + err_fi = v4l2_subdev_get_frame_interval(entity, &interval, pad);
>
> Not supporting frame intervals doesn't warrant a visible error message,
> I think -EINVAL should also be ignored above, if the spec is to be
> believed.
>
> >
> > printf("\t\t[fmt:%s/%ux%u",
> > v4l2_subdev_pixelcode_to_string(format.code),
> > format.width, format.height);
> >
> > - if (interval.numerator || interval.denominator)
> > + if (err_fi == 0 && (interval.numerator || interval.denominator))
> > printf("@%u/%u", interval.numerator, interval.denominator);
> > + else if (err_fi != -ENOTTY)
> > + printf("@<error: %s>", strerror(-err_fi));
>
> Or here.

I don't mind which - I could change this to:

else if (err_fi != -ENOTTY && err_fi != -EINVAL)

Or an alternative would be to print an error (ignoring ENOTTY and EINVAL)
to stderr at the "v4l2_subdev_get_frame_interval" callsite and continue
on (ensuring that interval is zeroed).

--
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