ACPI: Set max_cstate to 1 for early Opterons.

AMD Opteron processors before CG revision don't like C-states > 1.

This solves the long standing bugzilla #5303 and probably some more
on affected machines:

  http://bugzilla.kernel.org/show_bug.cgi?id=5303

[ tglx@linutronix.de: reworked the patch so it does not wreck ia64 ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 27 insertions, 0 deletions

diff --git a/include/asm-x86/acpi.h b/include/asm-x86/acpi.h
index 0693689d4146..f8a89793ac8c 100644
--- a/include/asm-x86/acpi.h
+++ b/include/asm-x86/acpi.h
@@ -1,5 +1,32 @@
+#ifndef _ASM_X86_ACPI_H
+#define _ASM_X86_ACPI_H
+
 #ifdef CONFIG_X86_32
 # include "acpi_32.h"
 #else
 # include "acpi_64.h"
 #endif
+
+#include <asm/processor.h>
+
+/*
+ * Check if the CPU can handle C2 and deeper
+ */
+static inline unsigned int acpi_processor_cstate_check(unsigned int max_cstate)
+{
+        /*
+         * Early models (<=5) of AMD Opterons are not supposed to go into
+         * C2 state.
+         *
+         * Steppings 0x0A and later are good
+         */
+        if (boot_cpu_data.x86 == 0x0F &&
+            boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+            boot_cpu_data.x86_model <= 0x05 &&
+            boot_cpu_data.x86_mask < 0x0A)
+                return 1;
+        else
+                return max_cstate;
+}
+
+#endif