EGL_MESA_screen_surface proposal

[Jon Smirl]

On Wed, 16 Mar 2005 13:15:23 -0500, Jon Smirl <jonsmirl at gmail.com> wrote:
> The root of the problem is that there are more attributes on the mode
> than are exposed in EGL. You could do a elgChooseMode(1024,768) and
> get back 10 identical modes at the EGL level, but they would all be
> different at the hardware level. EGL will pick the what it thinks is
> the best mode and you won't be able to get to the others since you
> can't tell them appart.

I think the key problem here is that elgChooseMode(1024,768) can
return more than one mode. I don't think you can make the argument
that you need to return more than one mode at each resolution. You
will want this to be the best mode possible, why would you want to set
an inferior one? But not enough information is returned through the
EGL API to actually determine what the best mode is at the given
resolution.

My first approach was to expand the amount of information available
about the modes. Now instead I would propose that the internal
implementation of the egl API should sort through the modes in all of
their gory detail and pick the best one. Then only this one would be
exposed via the egl API to upper layers.

Right now my monitor reports this from framebuffer:
U:1152x864-75,width=1152,height=864,refresh=75
D:1280x1024-60,width=1280,height=1024,refresh=60
V:1153x864-75,width=1153,height=864,refresh=75
V:1280x1024-75,width=1280,height=1024,refresh=75
V:1024x768-75,width=1024,height=768,refresh=75
V:1024x768-70,width=1024,height=768,refresh=70
V:1024x768-60,width=1024,height=768,refresh=60
U:832x624-75,width=832,height=624,refresh=75
V:800x600-75,width=800,height=600,refresh=75
V:800x600-72,width=800,height=600,refresh=72
V:800x600-60,width=800,height=600,refresh=60
V:800x600-56,width=800,height=600,refresh=56
V:640x480-75,width=640,height=480,refresh=75
V:640x480-72,width=640,height=480,refresh=72
U:640x480-67,width=640,height=480,refresh=67
V:640x480-60,width=640,height=480,refresh=60
U:720x400-70,width=720,height=400,refresh=70

I know that the detailed mode is the best mode possible:
D:1280x1024-60,width=1280,height=1024,refresh=60

My implementation of the egl API would then return the best mode at
each resolution. I might incorporate the knowledge that if the
detailed refresh rate is 60Hz that it make no sense to set the modes
at anything other than 60Hz. My list for egl would then look like
this:

U:1152x864-75,width=1152,height=864,refresh=75
D:1280x1024-60,width=1280,height=1024,refresh=60
V:1153x864-75,width=1153,height=864,refresh=75
V:1024x768-60,width=1024,height=768,refresh=60
U:832x624-75,width=832,height=624,refresh=75
V:800x600-60,width=800,height=600,refresh=60
V:640x480-60,width=640,height=480,refresh=60
U:720x400-70,width=720,height=400,refresh=70

which would then only be returned as a set of resolutions encoded in egl format
width=1152,height=864
width=1280,height=1024
width=1153,height=864
width=1024,height=768
width=832,height=624
width=800,height=600
width=640,height=480
width=720,height=400

Doesn't this simplify everything?

-- 
Jon Smirl
jonsmirl at gmail.com