From d4d25deca49ec2527a634557bf5a6cf449f85deb Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Mon, 26 Nov 2007 20:42:19 +0100 Subject: x86: fix NMI watchdog & 'stopped time' problem More than 3 years ago Niclas Gustafsson reported a 'stopped time' problem: > Watching the /proc/interrupts with 10s apart after the "stop". > > [root@s151 root]# more /proc/interrupts > CPU0 > 0: 66413955 local-APIC-edge timer [...] > LOC: 67355837 > ERR: 0 > MIS: 0 > [root@s151 root]# more /proc/interrupts > CPU0 > 0: 66413955 local-APIC-edge timer [...] > LOC: 67379568 > ERR: 0 > MIS: 0 This may be because buggy SMM firmware messes with the 8259A (configured for a transparent mode -- yes that rare "local-APIC-edge" mode is tricky ;-) ) insanely. this should resolve: http://bugzilla.kernel.org/show_bug.cgi?id=2544 http://bugzilla.kernel.org/show_bug.cgi?id=6296 Patch-dusted-off-by: Ingo Molnar Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/io_apic_32.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/io_apic_32.c') diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c index f35c6eb33da9..fc4bbc1d1331 100644 --- a/arch/x86/kernel/io_apic_32.c +++ b/arch/x86/kernel/io_apic_32.c @@ -2166,6 +2166,10 @@ static inline void __init check_timer(void) { int apic1, pin1, apic2, pin2; int vector; + unsigned int ver; + + ver = apic_read(APIC_LVR); + ver = GET_APIC_VERSION(ver); /* * get/set the timer IRQ vector: @@ -2179,11 +2183,15 @@ static inline void __init check_timer(void) * mode for the 8259A whenever interrupts are routed * through I/O APICs. Also IRQ0 has to be enabled in * the 8259A which implies the virtual wire has to be - * disabled in the local APIC. + * disabled in the local APIC. Finally timer interrupts + * need to be acknowledged manually in the 8259A for + * timer_interrupt() and for the i82489DX when using + * the NMI watchdog. */ apic_write_around(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT); init_8259A(1); - timer_ack = 1; + timer_ack = !cpu_has_tsc; + timer_ack |= (nmi_watchdog == NMI_IO_APIC && !APIC_INTEGRATED(ver)); if (timer_over_8254 > 0) enable_8259A_irq(0); -- cgit v1.2.3-59-g8ed1b