Real time clock (RTC) runs 50% too fast when speedstep is enabled

[Jason Bouzane]

Binary package hint: kernel-image-2.6.15-26-amd64-generic-di

I have an Intel Core 2 Duo 2.4 GHz CPU. When Speedstep is enabled and the CPU is slowed, the clock runs at 150% the normal speed. The timer interrupts continue to occur at 250/second as they should, but the clock runs too fast, leading to various system problems (sound too fast, lockups, hardware not functioning, etc.). When the CPU is busy (CPU is at full speed), the clock runs normally. Disabling speedstep fixes the problem.

Distribution: Kubuntu 6.06 amd64

[Matthew Garrett (mjg59)]

Is it possible to test a beta version of 6.10 on this machine? A live CD should do, there's no need to do a full install.

[Jason Bouzane (jbouzane)]

It doesn't boot. I suspect that change # 79e453d49bd49ba1b576f89310cc565c9e4ca379 will fix the problem (it's a 965 board).

See:

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=79e453d49bd49ba1b576f89310cc565c9e4ca379

Perhaps this revert should be applied to the base Kubuntu image before release?

[Jason Bouzane (jbouzane)]

The reason it doesn't boot with the new kernel is that the nvidiafb driver has a bug. The default Edgy Eft kernel fails to boot on my box.

[Jason Bouzane (jbouzane)]

This change will probably fix it. I haven't tried it yet, though:

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=aa026ede513b7d672fa7d9106b2f2a475455dcf2

It certainly sounds like the problem as I saw it only in C3.

[Bryan Quigley (bryanquigley)]

Has this been fixed?

[Jason Bouzane (jbouzane)]

Yes, though I can't see any place in this UI to close the bug.

[Bryan Quigley (bryanquigley)]

Clicking the dropdown button under status.