From 532cfee6ba0a8efcf7c3ce38b9881292d79d516e Mon Sep 17 00:00:00 2001
From: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Date: Thu, 11 Jun 2009 15:26:48 +0000
Subject: [PATCH] [CPUFREQ] powernow-k8: read P-state from HW
By definition, "cpuinfo_cur_freq" should report the value from HW. So, don't
depend on the cached value. Instead read P-state directly from HW, while
taking into account the erratum 311 workaround for Fam 11h processors.
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Langsdorf, Mark <mark.langsdorf@amd.com>
Cc: Thomas Renninger <trenn@suse.de>
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Reviewed-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Langsdorf, Mark <mark.langsdorf@amd.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
---
arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 25 ++++++++++-------------
1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
index 2709b3c183b4..331021112f2b 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -118,20 +118,17 @@ static int query_current_values_with_pending_wait(struct powernow_k8_data *data)
u32 i = 0;
if (cpu_family == CPU_HW_PSTATE) {
- if (data->currpstate == HW_PSTATE_INVALID) {
- /* read (initial) hw pstate if not yet set */
- rdmsr(MSR_PSTATE_STATUS, lo, hi);
- i = lo & HW_PSTATE_MASK;
-
- /*
- * a workaround for family 11h erratum 311 might cause
- * an "out-of-range Pstate if the core is in Pstate-0
- */
- if (i >= data->numps)
- data->currpstate = HW_PSTATE_0;
- else
- data->currpstate = i;
- }
+ rdmsr(MSR_PSTATE_STATUS, lo, hi);
+ i = lo & HW_PSTATE_MASK;
+ data->currpstate = i;
+
+ /*
+ * a workaround for family 11h erratum 311 might cause
+ * an "out-of-range Pstate if the core is in Pstate-0
+ */
+ if ((boot_cpu_data.x86 == 0x11) && (i >= data->numps))
+ data->currpstate = HW_PSTATE_0;
+
return 0;
}
do {
--
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