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>

3 files changed, 29 insertions, 0 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index f996d0e37689..b52109bd06d2 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1658,6 +1658,7 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
 
         if (!first_run) {
                 dmi_check_system(processor_power_dmi_table);
+                max_cstate = acpi_processor_cstate_check(max_cstate);
                 if (max_cstate < ACPI_C_STATES_MAX)
                         printk(KERN_NOTICE
                                "ACPI: processor limited to max C-state %d\n",
diff --git a/include/asm-ia64/acpi.h b/include/asm-ia64/acpi.h
index 49730ffbbae4..81bcd5e51789 100644
--- a/include/asm-ia64/acpi.h
+++ b/include/asm-ia64/acpi.h
@@ -94,6 +94,7 @@ ia64_acpi_release_global_lock (unsigned int *lock)
 #define acpi_noirq 0    /* ACPI always enabled on IA64 */
 #define acpi_pci_disabled 0 /* ACPI PCI always enabled on IA64 */
 #define acpi_strict 1   /* no ACPI spec workarounds on IA64 */
+#define acpi_processor_cstate_check(x) (x) /* no idle limits on IA64 :) */
 static inline void disable_acpi(void) { }
 
 const char *acpi_get_sysname (void);
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