[PATCH 1/2] man: add description for specifying modes with aspect-ratio in weston.ini
ppaalanen at gmail.com
Fri Jul 6 09:14:32 UTC 2018
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:
> +Specify a mode with a given refresh-rate measured in Hz.
> +\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.
> \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
If you look at weston.ini.man before your changes, you see that it has
.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
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.
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