AMD chip bug snares Linux users

The Register ^ | 01/22/02 | Andrew Orlowski

[peabers]

An old bug in AMD’s Athlon family of chips may still be snaring Linux users.

Affected users will need to be running a 2.4 kernel, an AGP and an Athlon or Duron CPU. At cause is a compatibility issue with Intel’s 4MB page size. (x86 processors have used 4k pages, ever since paging was introduced in the 80386).

AMD issued a patch for Windows users in Fall 2000, with an accompanying PDF [13k].

But all the patch is, is a one-line registry change, described here, that only disables the expanded page size. And not all Pentium-specific instructions.

For Linux users, it's a one line workaround, too. Pass the line “append mem=nopentium” at boot time (via your boot loader of choice), to disable all Pentium specific instructions.

News site Gentoo reported this yesterday, and found itself Slashdotted into the netherworld. It's still down, as we write. ®

[peabers]

I have suspected this all along, and even commented about it here a couple of weeks ago. I have been trying unsuccessfully for seven months to get Mandrake 8.0 and 8.1 to run stablely on two Athlon workstations. Mandrake 8.1 runs great on my one and only Intel box (PII 450).

[peabers]

Filing.

[woofer]

So is what your telling me is that I can't migrate to Linux with my AMD 14Ghz T-bird screamers?

[woofer]

OOPS! Sorry, that's 1 POINT 4 Ghz Athlons

[peabers]

Read the linked article at Gentoo for full details (the link is working, contrary to the last sentence in the article).

[Excuse_Me]

Does Mandrake 8.1 run on your Athlon once you add the appendmem=nopentium line?

[js1138]

my AMD 14Ghz T-bird screamers?

Great specs. Where did you get them?

[peabers]

So is what your telling me is that I can't migrate to Linux with my AMD 14Ghz T-bird screamers?

Yes you now can, if you implement the fix. The article at Gentoo mentioned in the last par explains the history of the problem. I had all but given up hope of running Linux as a desktop on my two screaming Athlon W/Stations. I believe the Athlon XP+ series is fully compatible with Pentium instruction set, including SSE.

[peabers]

Does Mandrake 8.1 run on your Athlon once you add the appendmem=nopentium line?

Haven't tried it yet, as I just stumbled across the article. It will have to wait until the weekend. But, the Gentoo article describes the problems I was having.

[Dark Watch]

I'd take up beating my wife before I'd buy another AMD processor. ....and people talk about Micro$oft.

[Michael Barnes]

I've never had a problem with my AMD's with any of the Linux distro's..What kind of problems were ya'll having?

[woofer]

Typo, It's 1.4, but it is a T-Bird.

[Mr. Peabody]

Mandrake 8.1 on Duron 900. What's the bug?