[PATCH 1/2] man: add description for specifying modes with aspect-ratio in weston.ini

[Nautiyal, Ankit K]

On 7/6/2018 2:44 PM, Pekka Paalanen wrote:
> On Tue, 19 Mar 2097 00:24:56 +0530
> "Nautiyal, Ankit K" <ankit.k.nautiyal at intel.com> wrote:
>
>> From: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>>
>> This patch adds information about the new resolution-format that can
>> be specified by a user in weston.ini to select a CEA mode. CEA defines
>> timing of a video mode, which is considered as a standard for
>> HDMI certification and compliance testing. It defines each and every
>> parameter, of  a video mode, like h/vactive,h/vfront h/vback etc.,
>> including aspect-ratio information. The drm layer, specifies the
>> aspect-ratio information in user-mode flag bits 19-22. For the non-CEA
>> modes a value of 0 is given in the aspect-ratio flag bits. Each
>> CEA-mode is identified by a unique, Video Identification Code (VIC).
>> For example, VIC=4 is 1280x720 at 60 aspect-ratio 16:9.
>> This mode will be different than a non-CEA mode 1280x720 at 60 0:0.
>>
>> The new mode-format helps to differentiate between the CEA and
>> non-CEA modes, by letting user specify aspect-ratio along with other
>> paremeters: mode=widthxheight at rr ratio.
>>
>> This helps when certification testing is done, in tests like 7-27,
>> the HDMI analyzer applies a particular CEA mode, and expects the
>> applied mode to be with exactly same timings, including the
>> aspect-ratio and VIC field.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>> ---
>>   man/weston-drm.man | 39 +++++++++++++++++++++++++++++++++++++--
>>   1 file changed, 37 insertions(+), 2 deletions(-)
>>
>> diff --git a/man/weston-drm.man b/man/weston-drm.man
>> index ae794423..f9247b27 100644
>> --- a/man/weston-drm.man
>> +++ b/man/weston-drm.man
>> @@ -64,8 +64,43 @@ can be one of the words
>>   .BR off " to turn the output off, "
>>   .BR preferred " to use the monitor's preferred video mode, or "
>>   .BR current " to use the current video mode and avoid a mode switch."
>> -It can also be a resolution as
>> -\fIwidth\fBx\fIheight\fR, or a detailed mode line as below.
>> +It can also be a resolution as:
>> +.TP
>> +\fBmode\fR=\fIwidth\fBx\fIheight\fR
>> +.TP
>> +\fBmode\fR=\fIwidth\fBx\fIheight\fB@\fIrefresh_rate\fR
>> +Specify a mode with a given refresh-rate measured in Hz.
>> +.TP
>> +\fBmode\fR=\fIwidth\fBx\fIheight\fB@\fIrefresh_rate ratio\fR
>> +Here \fIratio\fR is Picture Aspect-Ratio which can have values as 4:3, 16:9,
>> +64:27, and 256:135. This resolution-format helps to select a CEA mode, if such a
>> +video mode is present in the mode-list of the output.
>> +
>> +CEA defines the timing of a video mode, which is considered as a standard for
>> +HDMI spcification and compliance testing. It defines each and every parameter of
>> +a video mode, like hactive, vactive, vfront, vback etc., including aspect-ratio
>> +information. For CEA modes, the drm layer, stores this aspect-ratio information
>> +in user-mode (drmModeModeInfo) flag bits 19-22. For the non-CEA modes a value of
>> +0 is stored in the aspect-ratio flag bits.
>> +
>> +Each CEA-mode is identified by a unique, Video Identification Code (VIC).
>> +For example, VIC=4 is 1280x720 at 60 aspect-ratio 16:9. This mode will be
>> +different than a non-CEA mode 1280x720 at 60 0:0. When the video mode
>> +1280x720 at 60 0:0 is applied, since its timing doesnt exactly match with the CEA
>> +information for VIC=4, it would be treated as a non-CEA mode. Also, while setting
>> +the HDMI-AVI-Inforframe, VIC parameter will be given as '0'. If video mode
>> +1280x720 at 60 16:9 is applied, its CEA timimgs matches with that of video mode with
>> +VIC=4, so the VIC parameter in HDMI-AVI-Infoframe will be set to 4.
>> +
>> +Many a times, an output may have both CEA and non-CEA modes, which are similar
>> +in all resepct, differing only in the aspect-ratio. A user can select a CEA mode
>> +by giving the aspect-ratio, along with the other arguments for the mode.
>> +By omitting the aspect-ratio, user can specify the non-CEA modes.
>> +This helps when certification testing is done, in tests like 7-27, the
>> +HDMI-analyzer applies a particular CEA mode, and expects the applied mode to be
>> +with exactly same timings, including the aspect-ratio and VIC field.
>> +
>> +The resolution can also be a detailed mode line as below.
>>   .TP
>>   \fBmode\fR=\fIdotclock hdisp hsyncstart hsyncend htotal \
>>   vdisp vsyncstart vsyncend vtotal hflag vflag\fR
> Sorry, looks like I wasn't clear enough with what I meant with a
> separate patch.
>
> If you look at weston.ini.man before your changes, you see that it has
> the following:
>
> .BR "preferred       " "Uses the preferred mode"
> .BR "current         " "Uses the current crt controller mode"
> .BR "off             " "Disables the output"
>
> These options and the following discussion of a modeline apply only to
> the DRM-backend. My intention was to move those into weston-drm.man as
> patch 1.
>
> Then, patch 2 would add all the aspect ratio implementation with aspect
> ratio man page additions.
>
> However, this isn't a big problem, you did the man page just fine.

Hi Pekka,

I could see the mode options - preferred, current and off are already 
there in the weston-drm.man.
I will send another patch to remove these from weston.man.

Regards,
Ankit
>
> Thanks,
> pq