[Bug 349314] Re: [i915] allocate MCHBAR space & enable if necessary

Fri Apr 3 15:00:56 UTC 2009

I tried Andy's 2.6.28-11.38lp349314apw1 kernel on my Mac mini Core Duo
with Intel GMA950 on mdz's recommendation after following Bug #339555
and Bug #353245 but have inconclusive results.

After my initial Intrepid to Jaunty upgrade video performance was
basically unusable even with all Visual Effects disabled. Just moving
windows around the screen resulted in choppy refresh, and switching
workspaces took 2-3 seconds for all the windows to redraw.

I eventually tested using a Jaunty Desktop Beta i386 LiveCD and
performance was normal; video was just as fast, crisp, and smooth as I
was used to with Intrepid.

I then reboot back to the internal disk and video performance was
mysteriously better. Still not on par with Intrepid but usable. No
configuration changes or package upgrades were made.

A dist-upgrade was done to pick up the latest packages but still no
additional improvement.

I then installed Andy's 2.6.28-11.38lp349314apw1 kernel and performance
seems better compared to my original unusable Intrepid to Jaunty
upgrade, but performance doesn't come close to my test on the Jaunty
Desktop Beta i386 LiveCD.

Hence, my inconclusive results.

My unscientific test is simple...create 4 workspaces (2 rows, 2
columns), open a Firefox window on each workspace, then rapidly switch
between workspaces with Ctrl-Alt-Arrow. On Intrepid and the Jaunty
Desktop Beta i386 LiveCD switching workspaces is smooth and fluid. On my
upgraded Jaunty install it sometimes takes 2-3 seconds to switch
workspaces as the windows choppily animate across the screen.

00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)

(II) intel(0): Attempting memory allocation with tiled buffers.
(EE) intel(0): Failed to set tiling on front buffer: rejected by kernel
(EE) intel(0): Failed to set tiling on back buffer: rejected by kernel
(EE) intel(0): Failed to set tiling on depth buffer: rejected by kernel
(II) intel(0): Tiled allocation successful.

** Attachment added: "Xorg.0.log"
   http://launchpadlibrarian.net/24757453/Xorg.0.log

-- 
[i915] allocate MCHBAR space & enable if necessary
https://bugs.launchpad.net/bugs/349314
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