Re: desktop effects gone with kernel 2.6.30

[Cade Robinson <cade.robinson@gmail.com>]

On Thu, 2009-06-11 at 12:51 +0200, Marcus Better wrote:

> after upgrading from kernel 2.6.29.4 to 2.6.30, desktop effects cannot be 
> enabled anymore in KDE 4.2.4.

I am using:
linux-image-2.6.30-rc8-amd64 2.6.30~rc8-1~experimental.1~snapshot.13741
xserver-xorg-core            2:1.6.1.901-2
xserver-xorg-video-intel     2:2.7.99.1-2
xserver-xorg-core            2:1.6.1.901-2

OpenGL renderer string: Mesa DRI Intel(R) Q35 GEM 20090418 2009Q1

xorg.conf section:
Section "Device"
        Identifier      "Configured Video Device"
        Option          "AccelMethod"   "UXA"
EndSection

in /etc/modules:
i915 modeset=1

One thing I found was my MTRRs were messed up
you can "cat /proc/mtrr"

My reg0 was like 4GB and blocking the range my card wanted to use.
I have a /etc/rcS.d script to fix the MTRR range.

My current MTRR is:
cat /proc/mtrr
reg00: base=0x000000000 (    0MB), size= 2048MB, count=1: write-back
reg01: base=0x07d600000 ( 2006MB), size=    2MB, count=1: uncachable
reg02: base=0x07d800000 ( 2008MB), size=    8MB, count=1: uncachable
reg03: base=0x07e000000 ( 2016MB), size=   32MB, count=1: uncachable
reg04: base=0x07d500000 ( 2005MB), size=    1MB, count=1: uncachable
reg05: base=0x080000000 ( 2048MB), size= 2048MB, count=1: uncachable
reg06: base=0x0d0000000 ( 3328MB), size=  256MB, count=2:
write-combining

the script:
#!/bin/sh
# Fix wrong MTRR setting
#Empty File
echo -n "Fixing MTRR ... "
echo "disable=0" >| /proc/mtrr
#for X in $(cat /proc/mtrr | cut -c 5 | sort -rn)
#do
#       echo "disable=$X" >| /proc/mtrr
#done
#Set Correct settings:
#Possible Values:
#0x08000000 = 128Mb
#0x10000000 = 256Mb
#0x40000000 = 1Gb
#0x60000000 = 1.5Gb
#0x80000000 = 2Gb
# First Line : Main Memory ( my Case 2gb)
# Second Line : Video Card Mem  ( my case 256 mb)
# don't edit base=.... !!!

echo "base=0x0 size=0x80000000 type=write-back" >| /proc/mtrr
echo 'base=0xd0000000 size=0x10000000 type=write-combining'
>| /proc/mtrr
echo "Done"
###############################

I have seen that I probably don't need to add the write-combining range
as X added it but there have been reports of it going away and not
adding again if you logout without reboot.

To figure out your base addr and size look at lspci -vvv for your vid
card and find a line with "prefetchable" in it like:
Region 2: Memory at d0000000 (32-bit, prefetchable) [size=256M]

I noticed a huge increase in the effect speed doing this.