Re: [PATCH] media: usb: uvc: fill in description for unknown pixelformats

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Thorsten,

On Wed, May 31, 2023 at 01:48:51PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
> On 29.03.23 14:28, Hans Verkuil wrote:
> > If the fcc is 0 (indicating an unknown GUID format), then fill in the
> > description field in ENUM_FMT. Otherwise the V4L2 core will WARN.
> 
> What happened to this? It seems this fall through the cracks.

I've posted a better fix, see
https://lore.kernel.org/linux-media/20230506065809.24645-1-laurent.pinchart@ideasonboard.com/.
Of course, fate had it that it got reviewed exactly on the day when I started by holidays :-S I'm now back, and will send a pull request.

> BTW:
> 
> > Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> 
> Afaics it might be good to have these in here:
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217252
> Link: https://bugzilla.redhat.com/show_bug.cgi?id=2180107

I'll add those two links.

> A comment in the former is what brought me here.
> 
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> --
> Everything you wanna know about Linux kernel regression tracking:
> https://linux-regtracking.leemhuis.info/about/#tldr
> If I did something stupid, please tell me, as explained on that page.
> 
> #regzbot ^backmonitor:
> https://lore.kernel.org/lkml/dc8e5276-ef88-648f-9f0d-10151ea62c90@leemhuis.info/
> #regzbot poke
> 
> > Fixes: 50459f103edf ("media: uvcvideo: Remove format descriptions")
> > ---
> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > index 7aefa76a42b3..2f1ced1212cd 100644
> > --- a/drivers/media/usb/uvc/uvc_driver.c
> > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > @@ -256,6 +256,9 @@ static int uvc_parse_format(struct uvc_device *dev,
> >  		} else {
> >  			dev_info(&streaming->intf->dev,
> >  				 "Unknown video format %pUl\n", &buffer[5]);
> > +			snprintf(format->name, sizeof(format->name), "%pUl\n",
> > +				 &buffer[5]);
> > +
> >  			format->fcc = 0;
> >  		}
> > 
> > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> > index 35453f81c1d9..fc6f9e7d8506 100644
> > --- a/drivers/media/usb/uvc/uvc_v4l2.c
> > +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> > @@ -713,6 +713,10 @@ static int uvc_ioctl_enum_fmt(struct uvc_streaming *stream,
> >  	if (format->flags & UVC_FMT_FLAG_COMPRESSED)
> >  		fmt->flags |= V4L2_FMT_FLAG_COMPRESSED;
> >  	fmt->pixelformat = format->fcc;
> > +	if (format->name[0])
> > +		strscpy(fmt->description, format->name,
> > +			sizeof(fmt->description));
> > +
> >  	return 0;
> >  }
> > 
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index 9a596c8d894a..22656755a801 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -264,6 +264,8 @@ struct uvc_format {
> >  	u32 fcc;
> >  	u32 flags;
> > 
> > +	char name[32];
> > +
> >  	unsigned int nframes;
> >  	struct uvc_frame *frame;
> >  };

-- 
Regards,

Laurent Pinchart