EGL_MESA_screen_surface version 2

[Jon Smirl]

My new opinion on modes is:

1) modes only have two egl attributes, width & height
2) modes must have name
3) the internal egl implementation can return multiple modes for each
width & height, name is what differentiates them
4) the multiple mode list is sorted by the internal egl implementation
such that most preferable mode comes first and so on.
5) default egl mode choice will be first one in the list at the given
resolution.

Some observations:
1) Modes are only set on displays. Displays are used by humans. Humans
want mode names, not X modelines.
2) Displays are by definition the top most level and have UI's which
can present the mode list
3) EGL should not attempt to the order modes even on the refresh rate.
The example of LCDs being superior at 60Hz than 72Hz is a good
example. Only the lower level systems know how to order the modes. If
you want to change the ordering available in EGL you need to adjust
things at a lower level.
4) For Ian's case of beat frequency between monitors, the display
would start up in 72 and 75Hz. The user would then change one to 72Hz.
Or the XGL config could have a mode name in it to override the default
setting.
5) It's a requirement to support multiple modes at a given resolution.
For example I didn't know that sports and movies recorded for HDTV
look better at slightly different frame rates. Only the user knows if
they are watching a full screen playback of sports or movies and can
set the mode using the human readable names.

-- 
Jon Smirl
jonsmirl at gmail.com