EGL_MESA_screen_surface version 4

[Adam Jackson]

On Wednesday 23 March 2005 20:41, Jon Smirl wrote:
> On Wed, 23 Mar 2005 20:28:49 -0500, Adam Jackson <ajax at nwnk.net> wrote:
> > #    7. How should the notion of a screen's "native" mode be expressed?
> > #       For example, LDC panels have a native resolution and refresh rate
> > #       that looks best but other sub-optimal resolutions may be
> > supported. #
> > #       The mode attribute EGL_OPTIMAL_MESA will be set for modes which
> > #       best match the screen.  [M. Danzer]
> >
> > And then below where it says that EGL_OPTIMAL configs get bumped to the
> > head of the list (ie, have sort priority 1).
>
> I don't really like building knowledge of display technology types
> into the EGL sort rules. Refresh is an important attribute for CRTs,
> optimal is important to LCDs. What is the important attribute for a
> plasma display, how about a DLP projector? Are we going to have to
> rewrite the sort rules every time a new display technology is
> developed?

No, we make a best effort at it now, and add intelligent selection criteria to 
the X server.  As I've said several times now, if you don't specify an 
attribute when doing a mode select, you've stated that you don't care, and 
that the default sort order is fine.  This is the risk you take when you use 
defaults.

> Take the switch from CRTs to LCDs as an example of this. When we only
> had CRTs you always wanted to sort on refresh. But then LCDs came
> along. Now sorting on refresh gives the wrong answer and you want
> optimal on top. I'm sure new technology will disrupt the sort order
> again sometime in the future.

So either we encode knowledge of all possible display types into EGL, or we 
don't.  I vote we don't for now, because we can add it as a layered extension 
if it's really important.  The OPTIMAL attribute is probably a good enough 
solution for now.

- ajax
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