Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ab688059 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[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: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 2391c4b5

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;