[patch 53/55] [CPUFREQ] powernow-k8: Avoid Pstate MSR accesses on systems supporting CPB

From: Greg KH
Date: Fri Feb 10 2012 - 17:46:43 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Andreas Herrmann <andreas.herrmann3@xxxxxxx>

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@xxxxxxx>
Signed-off-by: Dave Jones <davej@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/cpufreq/powernow-k8.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -926,23 +926,24 @@ static int fill_powernow_table_pstate(st
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;
}


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