From: Andreas Herrmann <andreas.herrmann3@amd.com>
Date: Fri, 6 Jan 2012 14:56:31 +0000 (+0100)
Subject: powernow-k8: Avoid Pstate MSR accesses on systems supporting CPB
X-Git-Tag: firefly_0821_release~7541^2~1760
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=2d8a3a209b35f8301c86e7962f636a372a0d7cad;p=firefly-linux-kernel-4.4.55.git

powernow-k8: Avoid Pstate MSR accesses on systems supporting CPB

commit 201bf0f129e1715a33568d1563d9a75b840ab4d3 upstream.

Due to CPB we can't directly map SW Pstates to Pstate MSRs. Get rid of
the paranoia check. (assuming that the ACPI Pstate information is
correct.)

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index bce576d7478e..e0329f9fa40e 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -926,23 +926,24 @@ static int fill_powernow_table_pstate(struct powernow_k8_data *data,
 			invalidate_entry(powernow_table, i);
 			continue;
 		}
-		rdmsr(MSR_PSTATE_DEF_BASE + index, lo, hi);
-		if (!(hi & HW_PSTATE_VALID_MASK)) {
-			pr_debug("invalid pstate %d, ignoring\n", index);
-			invalidate_entry(powernow_table, i);
-			continue;
-		}
-
-		powernow_table[i].index = index;
-
 		/* Frequency may be rounded for these */
 		if ((boot_cpu_data.x86 == 0x10 && boot_cpu_data.x86_model < 10)
 				 || boot_cpu_data.x86 == 0x11) {
+
+			rdmsr(MSR_PSTATE_DEF_BASE + index, lo, hi);
+			if (!(hi & HW_PSTATE_VALID_MASK)) {
+				pr_debug("invalid pstate %d, ignoring\n", index);
+				invalidate_entry(powernow_table, i);
+				continue;
+			}
+
 			powernow_table[i].frequency =
 				freq_from_fid_did(lo & 0x3f, (lo >> 6) & 7);
 		} else
 			powernow_table[i].frequency =
 				data->acpi_data.states[i].core_frequency * 1000;
+
+		powernow_table[i].index = index;
 	}
 	return 0;
 }