Hi Sakari,
On Monday 28 November 2011 17:01:12 Sakari Ailus wrote:
> On Mon, Nov 28, 2011 at 12:37:34PM +0100, Laurent Pinchart wrote:
> > When mapping from a V4L2 pixel format to a media bus format in the
> > VIDIOC_TRY_FMT and VIDIOC_S_FMT handlers, the requested format may be
> > unsupported by the driver. Return a hardcoded format instead of
> > WARN()ing in that case.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> > ---
> >
> > drivers/media/video/omap3isp/ispvideo.c | 8 ++++----
> > 1 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/media/video/omap3isp/ispvideo.c
> > b/drivers/media/video/omap3isp/ispvideo.c index d100072..ffe7ce9 100644
> > --- a/drivers/media/video/omap3isp/ispvideo.c
> > +++ b/drivers/media/video/omap3isp/ispvideo.c
> > @@ -210,14 +210,14 @@ static void isp_video_pix_to_mbus(const struct
> > v4l2_pix_format *pix,
> >
> > mbus->width = pix->width;
> > mbus->height = pix->height;
> >
> > - for (i = 0; i < ARRAY_SIZE(formats); ++i) {
> > + /* Skip the last format in the loop so that it will be selected if no
> > + * match is found.
> > + */
> > + for (i = 0; i < ARRAY_SIZE(formats) - 1; ++i) {
> >
> > if (formats[i].pixelformat == pix->pixelformat)
> >
> > break;
> >
> > }
> >
> > - if (WARN_ON(i == ARRAY_SIZE(formats)))
> > - return;
> > -
> >
> > mbus->code = formats[i].code;
> > mbus->colorspace = pix->colorspace;
> > mbus->field = pix->field;
>
> In case of setting or trying an invalid format, instead of selecting a
> default format, shouldn't we leave the format unchanced --- the current
> setting is valid after all.
TRY/SET operations must succeed. The format we select when an invalid format
is requested isn't specified. We could keep the current format, but wouldn't
that be more confusing for applications ? The format they would get in
response to a TRY/SET operation would then potentially depend on the previous
SET operations.
--
Regards,
Laurent Pinchart
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