Re: [v4l-utils PATCH 4/4] media-ctl: List supported media bus formats

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

Hi Sakari,

On Tuesday 23 February 2016 22:24:00 Sakari Ailus wrote:
> On Tue, Feb 23, 2016 at 10:15:46PM +0200, Laurent Pinchart wrote:
> > On Tuesday 23 February 2016 17:15:15 Hans Verkuil wrote:
> >> On 02/23/2016 05:11 PM, Sakari Ailus wrote:
> >>> On Tue, Feb 23, 2016 at 01:18:53PM +0100, Hans Verkuil wrote:
> >>>> On 02/21/16 22:29, Sakari Ailus wrote:
> >>>>> Add a new topic option for -h to allow listing supported media bus
> >>>>> codes in conversion functions. This is useful in figuring out which
> >>>>> media bus codes are actually supported by the library. The numeric
> >>>>> values of the codes are listed as well.
> >>>>> 
> >>>>> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> >>>>> ---
> >>>>> 
> >>>>>  utils/media-ctl/options.c | 42 ++++++++++++++++++++++++++++++++----
> >>>>>  1 file changed, 38 insertions(+), 4 deletions(-)
> >>>>> 
> >>>>> diff --git a/utils/media-ctl/options.c b/utils/media-ctl/options.c
> >>>>> index 0afc9c2..55cdd29 100644
> >>>>> --- a/utils/media-ctl/options.c
> >>>>> +++ b/utils/media-ctl/options.c

[snip]

> >>>>> @@ -45,7 +47,8 @@ static void usage(const char *argv0)
> >>>>> 
> >>>>>  	printf("-V, --set-v4l2 v4l2	Comma-separated list of formats to
> >>>>>  	setup\n");
> >>>>>  	printf("    --get-v4l2 pad	Print the active format on a given
> >>>>> pad\n");
> >>>>>  	printf("    --set-dv pad	Configure DV timings on a given pad\n");
> >>>>> 
> >>>>> -	printf("-h, --help		Show verbose help and exit\n");
> >>>>> +	printf("-h, --help[=topic]	Show verbose help and exit\n");
> >>>>> +	printf("			topics:	mbus-fmt: List supported media bus pixel
> >>>>> codes\n");
> >>>>
> >>>> OK, this is ugly. It has nothing to do with usage help.
> >>>> 
> >>>> Just make a new option --list-mbus-fmts to list supported media bus
> >>>> pixel codes.
> >>>> 
> >>>> That would make much more sense.
> >>> 
> >>> I added it as a --help option argument in order to imply it's a part
> >>> of the program's usage instructions, which is what it indeed is. It's
> >>> not a list of media bus formats supported by a device.
> >>> 
> >>> A separate option is fine, but it should be clear that it's about just
> >>> listing supported formats. E.g. --list-supported-mbus-fmts. But that's
> >>> a long one. Long options are loooong.
> >> 
> >> --list-known-mbus-fmts will do the trick.
> > 
> > That doesn't feel right. Isn't it a help option, really, given that it
> > lists the formats you can use as command line arguments ?
> > 
> > Another option would actually be to always print the formats when the -h
> > switch is given. We could print them in a comma-separated list with
> > multiple formats per line, possibly dropping the numerical value, it
> > should hopefully not be horrible.
> 
> I'd prefer to keep the numerical value as well; the link validation code in
> drivers may print the media bus code at each end in case they do not match.
> To debug that, it's easy to grep that from the list media-ctl prints.

Grepping media-bus-formats.h shouldn't be difficult ;-)

To shorten the output, how about printing the numerical values as 0x%04x or 
%04x ?

-- 
Regards,

Laurent Pinchart