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[PATCH] x86_64: Don't enable ATI apicmaintimer workaround when the machine has C2 or C3 

Many laptops have problems with ticking the local APIC timer in C2/C3.
The code added earlier to use it by default on ATI didn't really work
for them. Don't enable it when the system supports C2/C3.

This doesn't fix the problem fully, but at least it's not worse than before.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2006-02-16 23:42:04 +01:00 committed by Linus Torvalds
parent 2391c4b594
commit ab68805955
1 changed files with 16 additions and 0 deletions
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16
arch/x86_64/kernel/io_apic.c
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@ -30,6 +30,9 @@
#include <linux/mc146818rtc.h>
#include <linux/acpi.h>
#include <linux/sysdev.h>
#ifdef CONFIG_ACPI
#include <acpi/acpi_bus.h>
#endif
#include <asm/io.h>
#include <asm/smp.h>
@ -260,6 +263,8 @@ __setup("apic", enable_ioapic_setup);
And another hack to disable the IOMMU on VIA chipsets.
... and others. Really should move this somewhere else.
Kludge-O-Rama. */
void __init check_ioapic(void)
{
@ -307,6 +312,17 @@ void __init check_ioapic(void)
case PCI_VENDOR_ID_ATI:
if (apic_runs_main_timer != 0)
break;
#ifdef CONFIG_ACPI
/* Don't do this for laptops right
right now because their timer
doesn't necessarily tick in C2/3 */
if (acpi_fadt.revision >= 3 &&
(acpi_fadt.plvl2_lat + acpi_fadt.plvl3_lat) < 1100) {
printk(KERN_INFO
"ATI board detected, but seems to be a laptop. Timer might be shakey, sorry\n");
break;
}
#endif
printk(KERN_INFO
"ATI board detected. Using APIC/PM timer.\n");
apic_runs_main_timer = 1;