Running flightgear 2.4.0 on my machine leads to roughly 1 FPS rendering. When I run the same command, but with LIBGL_ALWAYS_SOFTWARE=1, I get around 15 FPS.
ickle on IRC suggested that:
17:47 < ickle> jkt: that would imply that the driver is falling back to swrast, only it does so an GTT mapping which is much slower than regular memory
He also mentioned that one could fix this issue by lots of beer and that I shall talk to a gentleman called Kayden -- and that's what I'm doing now.
64bit Gentoo Linux, Thinkpad T420s
"2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)"
xf86-video-intel: 3c4f29820bca336af2c997bafc7ef288b455813c (using SNA)
Just tell me if you need more information.
Sorry this took so long. Fixed in Mesa master with:
Author: Kenneth Graunke <firstname.lastname@example.org>
Date: Mon Mar 5 13:54:29 2012 -0800
intel: Remove pointless software fallback for glBitmap on Gen6.
We already have a meta path below that works just fine; no apparent
regressions in oglconform.
NOTE: This is a candidate for the 8.0 branch.
Reviewed-by: Chad Versace <email@example.com>
on Dec 08, 2016 at 23:57:42.
(provided by the Example extension).