AMD Catalyst 8.6 Linux Driver

[Chris Clearwater]

I was able to regain the use of all 8GB of memory by building my MTRR tables by hand. What a pain, but it wasn't the fault of ATI's driver, it is my BIOS.

[alec]

I was able to regain the use of all 8GB of memory by building my MTRR tables by hand. What a pain, but it wasn't the fault of ATI's driver, it is my BIOS.

I am about to try to fix my mtrr. Could you give some tips or sources to study?
Is performance as good as before? (in memory related tasks)

[Chris Clearwater]

Can you paste the following things:

1) The output of 'cat /proc/mtrr'
2) Amount of GPU RAM
3) Amount of System RAM

Performance should be the same, you are just fixing bad mtrr entries.

[alec]

> cat /proc/mtrr 
reg00: base=0x00000000 (   0MB), size=4096MB: write-back, count=1
reg01: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1
reg02: base=0xd0000000 (3328MB), size= 256MB: uncachable, count=1
reg03: base=0x100000000 (4096MB), size=1024MB: write-back, count=1
reg04: base=0x130000000 (4864MB), size= 256MB: uncachable, count=1
reg05: base=0xcff00000 (3327MB), size=   1MB: uncachable, count=1

4GB ram, 512MB video RAM

[Chris Clearwater]

Do you have 1MB memory hole enabled in BIOS? It would say something like "Memory hole, 15MB-16MB". Disable it if you find the option (I have it in my Asus BIOS) and paste your new /proc/mtrr.

[alec]

I know the option, but there is no such thing in gigabyte ex38-ds5 BIOS
neither is there remap options

[ningo]

Opening a second Xserver freezes the system completely and I have to do a hard reboot.

[Vighy]

Opening a second Xserver freezes the system completely and I have to do a hard reboot.

4 xservers are too much!

since fglrx already uses 2 xservers on it's own

[TarIthildil]

I know the option, but there is no such thing in gigabyte ex38-ds5 BIOS
neither is there remap options

Hi!

Did you proceed somehow? I have the same Problem and just discovered this thread. ( GA-P45-DS3 with 4GB and Sapphire 4850 )

Regards,

ingo

[Chris Clearwater]

Sorry for not replying sooner. Here is the mtrr script I use for 4GB:

#!/bin/bash

echo "disable=0" >| /proc/mtrr
echo "disable=1" >| /proc/mtrr
echo "disable=2" >| /proc/mtrr
echo "disable=3" >| /proc/mtrr
echo "disable=4" >| /proc/mtrr

echo "base=0x00000000 size=0x80000000 type=write-back" >| /proc/mtrr
echo "base=0x80000000 size=0x40000000 type=write-back" >| /proc/mtrr
echo "base=0xc0000000 size=0x10000000 type=write-back" >| /proc/mtrr

echo "base=0xd0000000 size=0x10000000 type=uncachable" >| /proc/mtrr

echo "base=0x100000000 size=0x20000000 type=write-back" >| /proc/mtrr
echo "base=0x120000000 size=0x10000000 type=write-back" >| /proc/mtrr

It might be different depending on your configuration. The idea is the mask all your memory as "write-back", except for the PCI addressable space (256M) as "uncachable" and leave your video card memory (512M for 4850) unmasked. And you have to do this using power of 2 sized blocks.

Here is my /proc/mtrr after applying the script, notice the 256M unchachable area starting at 3.25GB and the 512M gap starting at 3.5GB:

reg00: base=0x00000000 (   0MB), size=2048MB: write-back, count=1
reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
reg04: base=0x100000000 (4096MB), size= 512MB: write-back, count=1
reg05: base=0x120000000 (4608MB), size= 256MB: write-back, count=1

Edit: It seems the reg03 was removed somehow, it was a 256M uncacheable area, maybe I am doing something wrong :-) I wish the BIOS reported the mtrr correctly.