Commit dfea91d5 authored by Suresh Siddha's avatar Suresh Siddha Committed by Linus Torvalds

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: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Tested-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Chris McDermott <lcm@linux.vnet.ibm.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: stable@kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 54ef91dc
......@@ -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;
......
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