intel(0): Failed to set up write-combining range...

My Xorg.0.log has this warning:

And indeed, the mtrr table seems to be full:

Code:

~$ cat /proc/mtrr 
reg00: base=0xfffe0000 (4095MB), size= 128KB: write-protect, count=1
reg01: base=0xfffc0000 (4095MB), size= 128KB: uncachable, count=1
reg02: base=0x00000000 (   0MB), size= 256MB: write-back, count=1
reg03: base=0x10000000 ( 256MB), size= 256MB: write-back, count=1
reg04: base=0x1f800000 ( 504MB), size=   8MB: uncachable, count=1
reg05: base=0x1f600000 ( 502MB), size=   2MB: uncachable, count=1
reg06: base=0x1f500000 ( 501MB), size=   1MB: uncachable, count=1
reg07: base=0x00000000 (   0MB), size= 128KB: uncachable, count=1

I was wondering if this is expected when running linux on Aone, does everyone get this same "issue"?
I'm running debian currently, and didn't remember to check if this happened with linpus too.. so I'd appreciate if someone running linpus could report back.

 

Put this:

Code:

echo "disable=4" > /proc/mtrr
echo "base=0x1f800000 size=0x800000 type=write-back" > /proc/mtrr

in your rc.S right after the line:

Code:

/etc/rc.d/rc.last &

Putting it in rc.local will not work since X have already started.

 

Thanks, that did the trick!
Have you (or anyone here) noted any undesireable side effects from using this?

Anyway, this "trick" seems to improve performance quite a lot in some OGL applications; my FPS on Freespace2 increased almost 100% :shock:

Seems to have no effect on GlxGears or GtkPerf though.

Thanks again cpchan.
-wess

 

No problem. You should also get better 3D performance if you put:

Code:

export INTEL_BATCH=1

in your /etc/profile.local or what ever profile file you are using.

No, I have not noticed any undesirable side effects.

Out of curiosity what is your approx. FPS in GlxGears? With my tweaks so far, I am getting between 1006.764 FPS to 1036.503 FPS.

 

Yes, that one I had in place already.

I'm getting about 955..960 FPS (using Intel driver 2.3.2).

Cheers!
-wess

 

with no change i have more 1100 fps in glxgears

but with glx in front of the screen and mania drive running in window : 300 fps

 

Linux 2.6.28 MTRR cleanup

The Linux kernel 2.6.28 and higher will consolidate the MTRRs for you. You need to build a kernel. Enable MTRR cleanup in "make menuconfig", set the enable value to "1", and the spare MTRR value to "1". It ends up with 4 MTRRs used when X is running, rather than the 8 used and no spares for X that we had before.

IMO this is a problem in the Aspire One BIOS, they should be setting their MTRRs as Linux does after consolidating them. But they don't care, because Windows uses PAT to access the graphics card, and doesn't need an MTRR to do this. Linux has PAT, but the subsystem necessary to use it (graphics memory allocator) is brand new and nobody is using them in drivers yet.