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* [patch 1/2] x86, apic: use physical mode for IBM summit platforms
@ 2010-01-18 20:10 Suresh Siddha
  2010-01-18 20:10 ` [patch 2/2] x86, apic: use logical flat for systems with <= 8 logical cpus Suresh Siddha
  0 siblings, 1 reply; 11+ messages in thread
From: Suresh Siddha @ 2010-01-18 20:10 UTC (permalink / raw)
  To: torvalds, hpa, mingo, tglx
  Cc: linux-kernel, Suresh Siddha, Chris McDermott,
	Ananth N Mavinakayanahalli, Yinghai Lu, stable

[-- Attachment #1: ibm_summit_oem_check_for_x64.patch --]
[-- Type: text/plain, Size: 1327 bytes --]

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. 32bit 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 <suresh.b.siddha@intel.com>
Tested-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Chris McDermott <lcm@linux.vnet.ibm.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: stable@kernel.org
---
 arch/x86/kernel/apic/apic_flat_64.c |    5 +++++
 1 file changed, 5 insertions(+)

Index: tip/arch/x86/kernel/apic/apic_flat_64.c
===================================================================
--- tip.orig/arch/x86/kernel/apic/apic_flat_64.c
+++ tip/arch/x86/kernel/apic/apic_flat_64.c
@@ -240,6 +240,11 @@ static int physflat_acpi_madt_oem_check(
 		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;



^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2010-02-10  6:28 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-01-18 20:10 [patch 1/2] x86, apic: use physical mode for IBM summit platforms Suresh Siddha
2010-01-18 20:10 ` [patch 2/2] x86, apic: use logical flat for systems with <= 8 logical cpus Suresh Siddha
2010-02-09 18:00   ` [tip:x86/urgent] x86, apic: Don't use logical-flat mode when CPU hotplug may exceed 8 CPUs tip-bot for Suresh Siddha
2010-02-09 18:47     ` Yinghai Lu
2010-02-10  2:01       ` Suresh Siddha
2010-02-10  2:26         ` Yinghai Lu
2010-02-10  3:00           ` Yinghai Lu
2010-02-10  3:03             ` H. Peter Anvin
2010-02-10  3:04               ` Yinghai Lu
2010-02-10  3:42         ` Yinghai Lu
2010-02-10  6:27         ` tip-bot for Suresh Siddha

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