diff --git a/[refs] b/[refs]
index 5704b711a4cc..dd38454906c9 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b0f3f28e0f14eb335f67bfaae33ce8b8d74fd58b
+refs/heads/master: b5e8acf66ff5db707c7e08df49fdf6b415878442
diff --git a/trunk/arch/x86/kernel/cpu/perf_counter.c b/trunk/arch/x86/kernel/cpu/perf_counter.c
index 6ebe9abf6aef..f5853718d4d3 100644
--- a/trunk/arch/x86/kernel/cpu/perf_counter.c
+++ b/trunk/arch/x86/kernel/cpu/perf_counter.c
@@ -959,20 +959,8 @@ static struct pmc_x86_ops *pmc_amd_init(void)
 
 	nr_counters_generic = 4;
 	nr_counters_fixed = 0;
-	counter_value_mask = ~0ULL;
-
-	rdmsrl(MSR_K7_PERFCTR0, old);
-	wrmsrl(MSR_K7_PERFCTR0, counter_value_mask);
-	/*
-	 * read the truncated mask
-	 */
-	rdmsrl(MSR_K7_PERFCTR0, counter_value_mask);
-	wrmsrl(MSR_K7_PERFCTR0, old);
-
-	bits = 32 + fls(counter_value_mask >> 32);
-	if (bits == 32)
-		bits = fls((u32)counter_value_mask);
-	counter_value_bits = bits;
+	counter_value_mask = 0x0000FFFFFFFFFFFFULL;
+	counter_value_bits = 48;
 
 	pr_info("AMD Performance Monitoring support detected.\n");