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

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

Hi Hans,

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
> >>> @@ -22,7 +22,9 @@
> >>>  #include <getopt.h>
> >>>  #include <stdio.h>
> >>>  #include <stdlib.h>
> >>> +#include <string.h>
> >>>  #include <unistd.h>
> >>> +#include <v4l2subdev.h>
> >>> 
> >>>  #include <linux/videodev2.h>
> >>> 
> >>> @@ -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.

-- 
Regards,

Laurent Pinchart