[PATCH] x86_64: Don't enable ATI apicmaintimer workaround when the machine has C2 or C3 (ab688059) · Commits · 戴 / test

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>

arch/x86_64/kernel/io_apic.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -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;

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