summaryrefslogtreecommitdiffstats
path: root/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.24/0043-cpufreq-ACPI-Fix-not-loading-acpi-cpufreq-driver-reg.patch
blob: 21c973d39c198f6dd36e1b9b38eb73d64ed90d20 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
From 8d63c0484f5ed79f498c5bf3e5b90de29555bcb7 Mon Sep 17 00:00:00 2001
From: Thomas Renninger <trenn@suse.de>
Date: Thu, 12 Jul 2012 12:24:33 +0200
Subject: [PATCH 043/109] cpufreq / ACPI: Fix not loading acpi-cpufreq driver
 regression

commit c4686c71a9183f76e3ef59098da5c098748672f6 upstream.

Commit d640113fe80e45ebd4a5b420b introduced a regression on SMP
systems where the processor core with ACPI id zero is disabled
(typically should be the case because of hyperthreading).
The regression got spread through stable kernels.
On 3.0.X it got introduced via 3.0.18.

Such platforms may be rare, but do exist.
Look out for a disabled processor with acpi_id 0 in dmesg:
ACPI: LAPIC (acpi_id[0x00] lapic_id[0x10] disabled)

This problem has been observed on a:
HP Proliant BL280c G6 blade

This patch restricts the introduced workaround to platforms
with nr_cpu_ids <= 1.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/acpi/processor_core.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index c850de4..eff7222 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -189,10 +189,12 @@ int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id)
 		 *     Processor (CPU3, 0x03, 0x00000410, 0x06) {}
 		 * }
 		 *
-		 * Ignores apic_id and always return 0 for CPU0's handle.
+		 * Ignores apic_id and always returns 0 for the processor
+		 * handle with acpi id 0 if nr_cpu_ids is 1.
+		 * This should be the case if SMP tables are not found.
 		 * Return -1 for other CPU's handle.
 		 */
-		if (acpi_id == 0)
+		if (nr_cpu_ids <= 1 && acpi_id == 0)
 			return acpi_id;
 		else
 			return apic_id;
-- 
1.7.7.6