man: add description for specifying modes with aspect-ratio in weston.ini

Graphics / Wayland / Weston - Ankit Nautiyal [intel.com] - 6 July 2018 09:09 EDT

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.

f82ff35e man: add description for specifying modes with aspect-ratio in weston.ini
man/weston-drm.man | 39 +++++++++++++++++++++++++++++++++++++--
1 file changed, 37 insertions(+), 2 deletions(-)

Upstream: cgit.freedesktop.org


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