From f82ff35e8e67de1d11f0ef2538864881b37993fe Mon Sep 17 00:00:00 2001 From: Ankit Nautiyal Date: Tue, 19 Mar 2097 00:24:56 +0530 Subject: [PATCH] man: add description for specifying modes with aspect-ratio in weston.ini 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@60 aspect-ratio 16:9. This mode will be different than a non-CEA mode 1280x720@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@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 Reviewed-by: Pekka Paalanen --- 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@60 aspect-ratio 16:9. This mode will be +different than a non-CEA mode 1280x720@60 0:0. When the video mode +1280x720@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@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