Commit 14d98cad authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[PATCH] x86_64: Add option to disable timer check

This works around the too fast timer seen on some ATI boards.

I don't feel confident enough about it yet to enable it by default, but give
users the option.

Patch and debugging from Christopher Allen Wing <>, with
minor tweaks (renamed the option and documented it)

Signed-off-by: default avatarAndi Kleen <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 607a1685
......@@ -25,6 +25,9 @@ APICs
noapictimer Don't set up the APIC timer
no_timer_check Don't check the IO-APIC timer. This can work around
problems with incorrect timer initialization on some boards.
Early Console
syntax: earlyprintk=vga
......@@ -42,6 +42,8 @@
int sis_apic_bug; /* not actually supported, dummy for compile */
static int no_timer_check;
static DEFINE_SPINLOCK(ioapic_lock);
......@@ -1601,7 +1603,7 @@ static inline void check_timer(void)
* Ok, does IRQ0 through the IOAPIC work?
if (timer_irq_works()) {
if (!no_timer_check && timer_irq_works()) {
if (nmi_watchdog == NMI_IO_APIC) {
......@@ -1671,6 +1673,13 @@ static inline void check_timer(void)
panic("IO-APIC + timer doesn't work! Try using the 'noapic' kernel parameter\n");
static int __init notimercheck(char *s)
no_timer_check = 1;
return 1;
__setup("no_timer_check", notimercheck);
* IRQ's that are handled by the PIC in the MPS IOAPIC case.
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