From db96b0a0e4158806fcf03945a870f9320e6bac9b Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Wed, 22 Oct 2008 18:00:09 +0400 Subject: [PATCH] x86: do_boot_cpu - check if we have ESR register Impact: fix APIC IRQ irregularities on certain older boxes We should touch the APIC ESR register if only we have it. The patch fixes the problem mentioned by Max Kellermann: http://lkml.org/lkml/2008/10/17/147 Bisected-by: Max Kellermann Signed-off-by: Cyrill Gorcunov [ mingo@elte.hu: build fix ] Signed-off-by: Ingo Molnar --- arch/x86/kernel/smpboot.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 7ece815ea63..7b109339731 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -893,9 +893,11 @@ do_rest: smpboot_setup_warm_reset_vector(start_ip); /* * Be paranoid about clearing APIC errors. - */ - apic_write(APIC_ESR, 0); - apic_read(APIC_ESR); + */ + if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) { + apic_write(APIC_ESR, 0); + apic_read(APIC_ESR); + } } /* -- 2.41.1