From: Suresh Siddha Date: Mon, 18 Jan 2010 20:10:48 +0000 (-0800) Subject: x86, apic: use physical mode for IBM summit platforms X-Git-Tag: v2.6.33-rc5~17 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dfea91d5a7c795fd6f4e1a97489a98e4e767463e;p=profile%2Fcommon%2Fkernel-common.git x86, apic: use physical mode for IBM summit platforms Chris McDermott from IBM confirmed that hurricane chipset in IBM summit platforms doesn't support logical flat mode. Irrespective of the other things like apic_id's, total number of logical cpu's, Linux kernel should default to physical mode for this system. The 32-bit kernel does so using the OEM checks for the IBM summit platform. Add a similar OEM platform check for the 64bit kernel too. Otherwise the linux kernel boot can hang on this platform under certain bios/platform settings. Signed-off-by: Suresh Siddha Tested-by: Ananth N Mavinakayanahalli Cc: Chris McDermott Cc: Yinghai Lu Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c index eacbd2b..e3c3d82 100644 --- a/arch/x86/kernel/apic/apic_flat_64.c +++ b/arch/x86/kernel/apic/apic_flat_64.c @@ -240,6 +240,11 @@ static int physflat_acpi_madt_oem_check(char *oem_id, char *oem_table_id) printk(KERN_DEBUG "system APIC only can use physical flat"); return 1; } + + if (!strncmp(oem_id, "IBM", 3) && !strncmp(oem_table_id, "EXA", 3)) { + printk(KERN_DEBUG "IBM Summit detected, will use apic physical"); + return 1; + } #endif return 0;