X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=drivers%2Facpi%2Fprocessor_perflib.c;h=53e7ac9403a7dc21502e90a698ef1b27ad668a37;hb=6bacaa9ddacb71c691d32c678d37bc59ffc71fac;hp=836bfe0690422855c80ecfe41895a4fe667bfd14;hpb=18a022de47bc11ee20d7d0f4dd72d42d2cfdc51c;p=~andy%2Flinux

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 836bfe06904..53e7ac9403a 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -340,6 +340,13 @@ static void amd_fixup_frequency(struct acpi_processor_px *px, int i)
 	if ((boot_cpu_data.x86 == 0x10 && boot_cpu_data.x86_model < 10)
 	    || boot_cpu_data.x86 == 0x11) {
 		rdmsr(MSR_AMD_PSTATE_DEF_BASE + index, lo, hi);
+		/*
+		 * MSR C001_0064+:
+		 * Bit 63: PstateEn. Read-write. If set, the P-state is valid.
+		 */
+		if (!(hi & BIT(31)))
+			return;
+
 		fid = lo & 0x3f;
 		did = (lo >> 6) & 7;
 		if (boot_cpu_data.x86 == 0x10)