modesetting and DRI2/3

[zahlenmeer at gmx.de]

Hey everyone,
I am struggling to understand how the modesetting driver and DRI play
together.
This is from Xorg.0.log:

[  2350.977] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[  2350.977] (II) modeset(0): using drv /dev/dri/card0
[  2350.984] (II) glamor: OpenGL accelerated X.org driver based.
[  2351.387] (II) modeset(0): [DRI2]   DRI driver: i965
[  2351.387] (II) modeset(0): [DRI2]   VDPAU driver: i965

And this is from glxinfo:

libGL: Using DRI3 for screen 0

I read that modesetting uses DRI3 by default so I am a bit surprised to
read something like "modeset(0): [DRI2]" in my logs. I also tried and
compiled xorg with the --disable-dri2 flag. In this case I get aiglx
errors that modesetting failed to initalize the DRI2 extension.
Could anyone explain this behaviour to me?

Kind regards