From 14d98cad82b78956957e95567b8b5fb38ec5859f Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 20 May 2005 14:27:59 -0700 Subject: [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: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/x86_64/boot-options.txt | 3 +++ arch/x86_64/kernel/io_apic.c | 11 ++++++++++- 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index 44b6eea60ece..b9e6be00cadf 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -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 diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c index ac7684324954..80e9b498c443 100644 --- a/arch/x86_64/kernel/io_apic.c +++ b/arch/x86_64/kernel/io_apic.c @@ -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? */ unmask_IO_APIC_irq(0); - if (timer_irq_works()) { + if (!no_timer_check && timer_irq_works()) { nmi_watchdog_default(); if (nmi_watchdog == NMI_IO_APIC) { disable_8259A_irq(0); @@ -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. -- cgit v1.2.2