DRI2 Design Wiki Page

[Keith Whitwell]

Kristian Høgsberg wrote:
> Hi,
> 
> I wrote up the DRI2 design on a wiki page here:
> 
>     http://wiki.x.org/wiki/DRI2
> 
> It's the result of the discussions we had during my redirected
> rendering talk and several follow up discussions with Keith Whitwell
> and Michel Daenzer.  Relative to the design I presented, the
> significant change is that we now track clip rects and buffer
> attachments in the drm as part of the drm_drawable_t.  We always have
> private back buffers and swap buffers is implemented in the drm.  All
> this taken together (also with the super-ioctl) means that we don't
> need an SAREA or a drm or drawable lock.
> 
> There is an issue with the design, though, related to how and when the
> DRI driver discovers that the front buffer has changed (typically
> resizing).  The problem is described in detail on the page, but in
> short, the problem is that we were hoping to only check for this at
> glXSwapBuffers() time, but we need to discover this earlier in many
> cases.  Keith W alluded to a "beginning of frame" synchronization
> point in a previous mail, which may work, but I'm not sure of the
> details there.

I added a couple of comments, but I'm not sure about the issues around 
contexts sharing a drawable/backbuffer and the effects of glXSwapBuffers 
in that case.  Brian may be able to help with this a little.

Keith