RE: [suse-amd64] PCI memory hole and remapping (was -> Re: [suse-amd64] Memory Problem: 3Gb instead of 4Gb, TYAN K8WE s2895, 2x252 Opteron )
If your BIOS is doing this (as opposed to you mucking with the settings), I need to get the AMD BIOS developers to talk to your BIOS developers.
That would be great. Please do that. What's shown above is indeed the mtrr settings that come from the bios. I didn't change anything. And that's the same on two different PCs (both iwth A8V), so it's not that just one PC is broken or sth... However, whatever problems I was reporting to ASUS, I never got anything helpful back, or a fix in the next release etc. They seem to ignore user bug reports, but I guess they won't ignore AMD...
What motherboard, BIOS vendor, and BIOS version are you using?
You may want to check if your BIOS has an option for "Discrete" or "continuous" usage of MTRRs. Experiment with both settings - I believe "discrete" should work better in a memory hoisting environmnet.
Unfortunately not! I read about other mainboards having this option in the bios and looked for it carefully, because other people reported they could fix the problem with the fglrx driver using this setting. Unfortunately, Asus didn't put such a setting in their latest release...
They're supposed to have done so, after a huge fuss we had over these issues last year. After you give me the motherboard models, BIOS vendor, and BIOS version I can hopefully get this resolved.
-Mark Langsdorf AMD, Inc.
Langsdorf, Mark wrote
You may want to check if your BIOS has an option for "Discrete" or "continuous" usage of MTRRs. Experiment with both settings - I believe "discrete" should work better in a memory hoisting environmnet.
Unfortunately not! I read about other mainboards having this option in the bios and looked for it carefully, because other people reported they could fix the problem with the fglrx driver using this setting. Unfortunately, Asus didn't put such a setting in their latest release...
They're supposed to have done so, after a huge fuss we had over these issues last year. After you give me the motherboard models, BIOS vendor, and BIOS version I can hopefully get this resolved.
It's an Asus A8V Deluxe (not the A8V-E Deluxe). The bios is an AMI bios, revision 1013. This is the latest stable bios from the Asus webpage (was already onboard when I bought the motherboard).
There is a newer 1014 beta version, which I tried to test. But all efforts to update the bios on these mainboards fail, so I can't tell if the feature is available in the beta bios...
Thanks for caring! cu, Frank
Frank Steiner wrote
There is a newer 1014 beta version, which I tried to test. But all efforts to update the bios on these mainboards fail, so I can't tell if the feature is available in the beta bios...
I managed to install this bios, but it is even worse: With memory remapping enabled, the mtrr are still wrong (just like before), but there are now only 3.3GB of memory available (unlike 4GB with the stable bios and memory remapping activated).
And still no option for mtrr mapping...
cu, Frank
Hi Mark,
Langsdorf, Mark wrote
Ok, so I tried to play around with that a little bit. With memory remapping, /proc/mtrr looks like that:
reg00: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1 reg01: base=0x100000000 (4096MB), size= 512MB: write-back, count=1 reg02: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1 reg03: base=0xe0000000 (3584MB), size= 128MB: write-combining, count=1
This doesn't work. If your BIOS is doing this (as opposed to you mucking with the settings), I need to get the AMD BIOS developers to talk to your BIOS developers.
sorry for warming up such an old thread :-) I just tested the latest beta bios for the Asus A8V Deluxe (1015.002 from Oct 19th) to check if they had added sth. about discrete/continuous MTRRs. Unfortunately they still haven't. What's changed is the amount of memory available without remapping the memory hole: At least 3.8 of the 4GB are available, in contrats to 3.5 and 3.3 with earlier bios versions.
However, with "hardware memory hole" enabled in the bios, all the 4 GB are available for linux, but things like fglrx still can't load and the /proc/mtrr looks like this:
cantor:~ # cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1 reg01: base=0x100000000 (4096MB), size= 256MB: write-back, count=1 reg02: base=0xf0000000 (3840MB), size= 256MB: uncachable, count=1 reg03: base=0xf0000000 (3840MB), size= 128MB: write-combining, count=1
Do you see a chance to get the AMD bios guys make the ASUS people do *some* real work at last? ;-))
cu, Frank
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Frank Steiner -
Langsdorf, Mark