Bug 6497

Summary:	timer at double of normal speed
Product:	Timers	Reporter:	Marijn Schouten (M.Schouten)
Component:	Realtime Clock	Assignee:	timers_realtime-clock
Status:	RESOLVED PATCH_ALREADY_AVAILABLE
Severity:	normal	CC:	hugh, john.stultz, rohlfing
Priority:	P2
Hardware:	i386
OS:	Linux
Kernel Version:	2.6.16.14	Subsystem:
Regression:	---	Bisected commit-id:

Description Marijn Schouten 2006-05-05 09:58:32 UTC

forked from http://bugzilla.kernel.org/show_bug.cgi?id=3927 per Andi Kleen's 
request.

Most recent kernel where this bug did not occur: none
Distribution: Gentoo
Hardware Environment: Athlon64 3200+ MSI RS482M4 (Ati rs482 and sb450)
Software Environment: bash/date
Problem Description: the timer runs twice as fast as expected, looking at your 
watch and running date for two consecutive seconds produces a time difference 
of two seconds instead of only one.

Steps to reproduce: boot kernel without noapic, login, run date with one second 
intervals. Watch it report dates with 2 second intervals.
Workaround: boot with noapic

Comment 1 Marijn Schouten 2006-05-07 05:58:38 UTC

The previous situation is with ACPI disabled in BIOS. If I enable ACPI in BIOS 
and try to boot 2.6.16.14 without noapic then I get the following kernel panic:
not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

Comment 2 Marijn Schouten 2006-05-07 09:37:57 UTC

I've checked back to version 2.6.12 but none completely boot with ACPI enabled.

Comment 3 Marijn Schouten 2006-05-18 07:48:30 UTC

I was able to get ACPI working (see 
http://bugzilla.kernel.org/show_bug.cgi?id=6522) and this has allowed me to 
remove the noapic option without getting a double speed timer.