From: Andi Kleen <ak@suse.de>
Date: Thu, 16 Feb 2006 22:42:04 +0000 (+0100)
Subject: [PATCH] x86_64: Don't enable ATI apicmaintimer workaround when the machine has C2...
X-Git-Tag: firefly_0821_release~37981
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ab68805955ee3dd84a6aa76cd70e61fde996968d;p=firefly-linux-kernel-4.4.55.git
[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>
---
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;