diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-04-07 11:02:23 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-04-07 11:02:23 -0700 |
| commit | fb1ae635772d679eb312fa447290fc02cd0e4cf1 (patch) | |
| tree | 45733f9820da1190cd58bfff080edbb02af961a8 /arch/x86/kernel/hpet.c | |
| parent | addb2d6c13993060ae75f5005815b19dd2abdd64 (diff) | |
| parent | 472a474c6630efd195d3738339fd1bdc8aa3b1aa (diff) | |
Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
x86: Fix double enable_IR_x2apic() call on SMP kernel on !SMP boards
x86: Increase CONFIG_NODES_SHIFT max to 10
ibft, x86: Change reserve_ibft_region() to find_ibft_region()
x86, hpet: Fix bug in RTC emulation
x86, hpet: Erratum workaround for read after write of HPET comparator
bootmem, x86: Fix 32bit numa system without RAM on node 0
nobootmem, x86: Fix 32bit numa system without RAM on node 0
x86: Handle overlapping mptables
x86: Make e820_remove_range to handle all covered case
x86-32, resume: do a global tlb flush in S4 resume
Diffstat (limited to 'arch/x86/kernel/hpet.c')
| -rw-r--r-- | arch/x86/kernel/hpet.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index d10a7e7294f..23b4ecdffa9 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -400,9 +400,15 @@ static int hpet_next_event(unsigned long delta, * then we might have a real hardware problem. We can not do * much about it here, but at least alert the user/admin with * a prominent warning. + * An erratum on some chipsets (ICH9,..), results in comparator read + * immediately following a write returning old value. Workaround + * for this is to read this value second time, when first + * read returns old value. */ - WARN_ONCE(hpet_readl(HPET_Tn_CMP(timer)) != cnt, + if (unlikely((u32)hpet_readl(HPET_Tn_CMP(timer)) != cnt)) { + WARN_ONCE(hpet_readl(HPET_Tn_CMP(timer)) != cnt, KERN_WARNING "hpet: compare register read back failed.\n"); + } return (s32)(hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0; } @@ -1144,6 +1150,7 @@ int hpet_set_periodic_freq(unsigned long freq) do_div(clc, freq); clc >>= hpet_clockevent.shift; hpet_pie_delta = clc; + hpet_pie_limit = 0; } return 1; } |