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

[Hans Verkuil <hverkuil@xs4all.nl>]

On 02/23/16 21:30, Laurent Pinchart wrote:
> 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 ?

The help arguments don't have 'options'. You could provide a --help-list-mbus-fmts,
though.

>>> 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.

Just always printing the list when -h is given works for me too.

Regards,

	Hans

>>
>> 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 ?
>