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authorAndi Kleen <ak@suse.de>2006-02-16 23:42:04 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-17 08:00:40 -0800
commitab68805955ee3dd84a6aa76cd70e61fde996968d (patch)
treeabeaadcc28a6d60ca31fe85a732ace6a6df1232e /arch/x86_64
parent2391c4b594eb28abd58102de8f4e5d7a4fa39f4c (diff)
downloadlinux-ab68805955ee3dd84a6aa76cd70e61fde996968d.tar.bz2
[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>
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/kernel/io_apic.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index 4282d72b2a26..2585c1d92b26 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -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;