x86: prevent C-states hang on AMD C1E enabled machines
Impact: System hang when AMD C1E machines switch into C2/C3
AMD C1E enabled systems do not work with normal ACPI C-states
even if the BIOS is advertising them. Limit the C-states to
C1 for the ACPI processor idle code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/acpi.h b/include/asm-x86/acpi.h
index 635d764..35d1743 100644
--- a/include/asm-x86/acpi.h
+++ b/include/asm-x86/acpi.h
@@ -140,6 +140,8 @@
boot_cpu_data.x86_model <= 0x05 &&
boot_cpu_data.x86_mask < 0x0A)
return 1;
+ else if (boot_cpu_has(X86_FEATURE_AMDC1E))
+ return 1;
else
return max_cstate;
}