Hi Bastian,
On Monday 05 September 2011 11:51:52 Bastian Hecht wrote:
> 2011/9/5 Laurent Pinchart:
> > On Monday 05 September 2011 11:41:28 Bastian Hecht wrote:
> >> 2011/9/5 Laurent Pinchart:
> >> > On Monday 05 September 2011 11:10:48 Bastian Hecht wrote:
> >> >> 2011/8/31 Laurent Pinchart:
> >> >> >> > static int ov5642_g_crop(struct v4l2_subdev *sd, struct
> >> >> >> > v4l2_crop *a) {
> >> >> >> >
> >> >> >> > + struct i2c_client *client = v4l2_get_subdevdata(sd);
> >> >> >> > + struct ov5642 *priv = to_ov5642(client);
> >> >> >> >
> >> >> >> > struct v4l2_rect *rect = &a->c;
> >> >> >> >
> >> >> >> > - a->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> >> >> >> > - rect->top = 0;
> >> >> >> > - rect->left = 0;
> >> >> >> > - rect->width = OV5642_WIDTH;
> >> >> >> > - rect->height = OV5642_HEIGHT;
> >> >> >> > + a->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> >> >> >>
> >> >> >> Shouldn't you return an error instead when a->type is not
> >> >> >> V4L2_BUF_TYPE_VIDEO_CAPTURE ?
> >> >>
> >> >> No idea, but if you say so, I'll change it.
> >> >
> >> > VIDIOC_G_FMT documentation states that
> >> >
> >> > "When the requested buffer type is not supported drivers return an
> >> > EINVAL error code."
> >> >
> >> > I thought VIDIOC_G_CROP documentation did as well, but it doesn't.
> >> > However I believe the above should apply to VIDIOC_G_CROP as well.
> >> > There is no explicit documentation about error codes for subdev
> >> > operations, but I think it makes sense to follow what the V4L2 ioctls
> >> > do.
> >>
> >> And these ioctl calls go straight through to my driver? Or is there
> >> some intermediate work by the subdev architecture? I'm asking because
> >> I don't check the buffer type in g_fmt as well. If so, I have to
> >> change that too.
> >
> > The ioctls go to the host/bridge driver, which then decides when and how
> > to call g/s_fmt and g/s_crop. I would add the same check to g_fmt.
>
> Next time I will work in the media section of the kernel, I must study
> the docs a bit better I guess :/
Studying the docs isn't very difficult, the real problem is understanding what
is not written in the documentation :-)
> To the g_fmt() thing... is there the buffer type given at all? The
> argument of type struct v4l2_mbus_framefmt doesn't contain it.
Oops, my bad. You're right, there's no buffer type argument to the mbus
g/s_fmt calls. Sorry for the mistake.
--
Regards,
Laurent Pinchart
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