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>
diff --git a/include/asm-x86/acpi.h b/include/asm-x86/acpi.h
index 0693689..f8a8979 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