DRI2 Design Wiki Page

[Kristian Høgsberg]

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.

cheers,
Kristian