EGL_MESA_screen_surface version 2

[Benjamin Herrenschmidt]

On Thu, 2005-03-17 at 23:46 -0500, Jon Smirl wrote:
> My new opinion on modes is:
> 
> 1) modes only have two egl attributes, width & height

That is not new, and I still think you are wrong :) I think frequency is
important (you seem to be the only one not to think so). I also really
want more attributes, one important one for example is the LCD pixel
format (for subpixel rendering) etc... I'll try to come up with a proper
list asap. I need to read the spec first, this week-end hopefully.

> 2) modes must have name

Agreed.

> 3) the internal egl implementation can return multiple modes for each
> width & height, name is what differentiates them

You mean the frequency should be just part of the name ? Hrm... maybe. I
still want more attributes though :) What about things like TV standard,
etc... putting it all in the name will end up with quite over-long
names ...

> 4) the multiple mode list is sorted by the internal egl implementation
> such that most preferable mode comes first and so on.

So the LCD native mode would just be the first one returned by EGL ?
Agreed, that makes things simper, no need for a special "native"
attribute then.

> 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.

True, nobody wants actual timings, I think everybody agrees there.

> 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.