Bug 7789 - AMD64/ATI : timer is running twice as fast as it should
Summary: AMD64/ATI : timer is running twice as fast as it should
Alias: None
Product: Platform Specific/Hardware
Classification: Unclassified
Component: x86-64 (show other bugs)
Hardware: i386 Linux
: P2 normal
Assignee: Andi Kleen
Depends on:
Reported: 2007-01-08 05:14 UTC by Timo Jyrinki
Modified: 2007-02-13 12:46 UTC (History)
3 users (show)

See Also:
Kernel Version: 2.6.20-rc4
Regression: ---
Bisected commit-id:

dmesg-2.6.19.log (19.01 KB, text/plain)
2007-01-08 05:15 UTC, Timo Jyrinki
dmesg-2.6.20.log (19.53 KB, text/plain)
2007-01-08 05:16 UTC, Timo Jyrinki
lspci -nvv output (8.54 KB, text/plain)
2007-01-08 05:17 UTC, Timo Jyrinki
lspci -vv (10.11 KB, text/plain)
2007-01-08 05:18 UTC, Timo Jyrinki
patch to revert the possible culprit (6.06 KB, patch)
2007-01-08 12:14 UTC, Adrian Bunk
Details | Diff
dmesg-2.6.20-patched.log (18.89 KB, text/plain)
2007-01-08 13:43 UTC, Timo Jyrinki

Description Timo Jyrinki 2007-01-08 05:14:39 UTC
I'm creating a new bug as it was suggested in bug 3927. In 2.6.20, there is a
regression on at least my ATI board (and thus probably others) that the clock
runs at double speed. The most likely culprit is

I will attach dmesg logs from 2.6.19 and 2.6.20-rc4, plus lspci outputs.

Note that the following lines are missing from 2.6.20 dmesg output:
[ 0.000000] ATI board detected. Disabling timer routing over 8254.
[ 31.368871] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
Comment 1 Timo Jyrinki 2007-01-08 05:15:45 UTC
Created attachment 10028 [details]
Comment 2 Timo Jyrinki 2007-01-08 05:16:22 UTC
Created attachment 10029 [details]
Comment 3 Timo Jyrinki 2007-01-08 05:17:13 UTC
Created attachment 10030 [details]
lspci -nvv output
Comment 4 Timo Jyrinki 2007-01-08 05:18:21 UTC
Created attachment 10031 [details]
lspci -vv
Comment 5 Adrian Bunk 2007-01-08 12:14:51 UTC
Created attachment 10034 [details]
patch to revert the possible culprit

Does applying this patch fix the issue?
Comment 6 Timo Jyrinki 2007-01-08 13:43:58 UTC
Created attachment 10035 [details]

Confirming that using that revert patch fixes the issue and clock works
normally again.

ak's original git comment had "TBD Experimental. Needs a lot of testing", so if
it hasn't received that testing it'd probably be good to revert this. I'm happy
to test any future patches to the issue with my hardware.
Comment 7 Adrian Bunk 2007-01-08 19:02:10 UTC
The commit that broke it got reverted in Linus' tree.

Thanks for your bug report!
Comment 8 Timo Jyrinki 2007-01-11 08:32:00 UTC
post scriptum: the board is MSI RS482M4-ILD with the latest (and probably last)
BIOS version 1.2. I'm now trying to follow linux-kernel on possible 2.6.21
patches regarding this issue.

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