[utah-glx-dev] [torvalds@transmeta.com: i845 driver and MTRR's..]

[Philip B. <ph...@bo...>]

A note of interest, from the dri-devel mailing list.

Not interesting so much for the i845 chip, but for the speed comparison
between having mtrr, and not having mtrr

10FPS vs 30FPS? wow.

It's also interesting to note that with increased speed, comes increased
responsibility :-) you have to flush the cache, with MTRR.


----- Forwarded message from Linus Torvalds <tor...@tr...> -----

From: Linus Torvalds <tor...@tr...>
To: DRI Devel <dri...@li...>
Subject: [Dri-devel] i845 driver and MTRR's..


Am I the only one who gets _major_ texture corruption and flashing when 
enabling MTRR's on the i845 core? It migth happen with other chiptsets 
too, but the only one I've verified is i845.

Without MTRR's, things look good, but performance is not very pretty (at 
around 10 fps on "tuxracer" at 1024x768). No visual anomalies.

With MTRR's enabled, performance improves a lot ( ~30 fps or more), but 
there's a lot of corruption on-screen. Something isn't flushing caches.

----- End forwarded message -----