From: Yinghai Lu Date: Thu, 22 Dec 2011 01:45:17 +0000 (-0800) Subject: x86, x2apic: Fallback to xapic when BIOS doesn't setup interrupt-remapping X-Git-Tag: v3.3-rc1~189^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fb209bd891645bb87b9618b724f0b4928e0df3de;p=pandora-kernel.git 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 Signed-off-by: Yinghai Lu Link: http://lkml.kernel.org/r/20111222014632.600418637@sbsiddha-desk.sc.intel.com Signed-off-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- Reading git-diff-tree failed