diff options
| author | Yinghai Lu <yinghai@kernel.org> | 2011-12-21 17:45:17 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2011-12-23 11:01:01 -0800 |
| commit | fb209bd891645bb87b9618b724f0b4928e0df3de (patch) | |
| tree | 3b59766238dfedbe9f2164048008f4bb2c18a54e /arch/x86/kernel/apic/io_apic.c | |
| parent | a35fd28256e7736cc84af8931a16224f0bfaaf6c (diff) | |
| download | lwn-fb209bd891645bb87b9618b724f0b4928e0df3de.tar.gz lwn-fb209bd891645bb87b9618b724f0b4928e0df3de.zip | |
x86, x2apic: Fallback to xapic when BIOS doesn't setup interrupt-remapping
On some of the recent Intel SNB platforms, by default bios is pre-enabling
x2apic mode in the cpu with out setting up interrupt-remapping.
This case was resulting in the kernel to panic as the cpu is already in
x2apic mode but the OS was not able to enable interrupt-remapping (which
is a pre-req for using x2apic capability).
On these platforms all the apic-ids are < 255 and the kernel can fallback to
xapic mode if the bios has not enabled interrupt-remapping (which is
mostly the case if the bios has not exported interrupt-remapping tables to the
OS).
Reported-by: Berck E. Nash <flyboy@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20111222014632.600418637@sbsiddha-desk.sc.intel.com
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel/apic/io_apic.c')
| -rw-r--r-- | arch/x86/kernel/apic/io_apic.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 6d939d7847e2..45b461fdb344 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -2948,6 +2948,10 @@ static inline void __init check_timer(void) } local_irq_disable(); apic_printk(APIC_QUIET, KERN_INFO "..... failed :(.\n"); + if (x2apic_preenabled) + apic_printk(APIC_QUIET, KERN_INFO + "Perhaps problem with the pre-enabled x2apic mode\n" + "Try booting with x2apic and interrupt-remapping disabled in the bios.\n"); panic("IO-APIC + timer doesn't work! Boot with apic=debug and send a " "report. Then try booting with the 'noapic' option.\n"); out: |