[PATCH v2] compositor-drm: Add the aspect ratio parsing support

[Nautiyal, Ankit K]

Hi Pekka,

I have sent the next version of the patch with the review comments 
addressed, it got a bit delayed, due to addition of the DRM CLIENT CAP 
for aspect-ratio.

So Weston will call now the drmSetClientCap to show that it understands 
the aspect_ratio flags from the DRM layer.

If for some reason, DRM does not support the aspect ratio, weston will 
skip the reading of the aspect-ratio bits from drmModeModeInfo struct.

As discussed in #dri-devel with Daniel Vetter and Daniel Stone, its 
clear that the aspect ratio patch in weston will get r-b tags first, 
followed by

the r-b tags and merge from kernel side, followed by merge in weston.

Thanks,

Ankit

On 10/5/2017 6:41 PM, Pekka Paalanen wrote:
> On Thu, 5 Oct 2017 16:28:37 +0530
> "Nautiyal, Ankit K" <ankit.k.nautiyal at intel.com> wrote:
>
>> Hi Pekka,
>>
>> Thanks a lot for your review comments and the suggestions, and pointing
>> out the things I had missed.
>>
>> I agree to most of the changes, please find my response inline.
>>
>> I will shortly send the next version of the patch in a couple of days.
> Hi Ankit,
>
> excellent. I presume the plan is to get some R-b tags for Weston, then
> land the kernel patches (if they are not already?) and then land the
> Weston patch?
>
>>>> diff --git a/man/weston.ini.man b/man/weston.ini.man
>>>> index 4cfefc9..16965aa 100644
>>>> --- a/man/weston.ini.man
>>>> +++ b/man/weston.ini.man
>>>> @@ -363,10 +363,12 @@ The DRM backend accepts different modes:
>>>>    .PP
>>>>    .RS 10
>>>>    .nf
>>>> -.BR "WIDTHxHEIGHT    " "Resolution size width and height in pixels"
>>>> -.BR "preferred       " "Uses the preferred mode"
>>>> -.BR "current         " "Uses the current crt controller mode"
>>>> -.BR "off             " "Disables the output"
>>>> +.BR "WIDTHxHEIGHT    			" "Resolution size width and height in pixels"
>>>> +.BR "WIDTHxHEIGHT at RR			" "Resolution as above and refresh-rate in Hertz"
>>>> +.BR "WIDTHxHEIGHT at RR L:B    		" "Resolution as above and aspect-ratio as length:breadth"
>>> Is length and breadth really the official terminology? Intuitively I
>>> would be confused by what they mean.
>>>
>>> Since we can only parse a small fixed list of possible aspect-ratio
>>> strings, it would be nice to list the valid strings.
>> Length Breadth is not official terminology, I just wanted to distinguish
>> from width and height of the mode.
>> Since we have just a few valid aspect-ratio, it makes sense to add that
>> as an example.
> Ah, ok. Yes, distinguishing from width and height is important.
> You could easily side-step the whole terminology by simply using
>
> 	WIDTHxHEIGHT at RR RATIO
>
> and simply listing the possible values for RATIO. Or similar.
>
> Thanks,
> pq
>
>
>>>> +.BR "preferred       			" "Uses the preferred mode"
>>>> +.BR "current         			" "Uses the current crt controller mode"
>>>> +.BR "off             			" "Disables the output"
>>>>    .fi
>>>>    .RE
>>>>    .RS
>>> Man page update is good.
>>>
>>>
>>> Thanks,
>>> pq
>> Thanks & Regards,
>> Ankit