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

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

From: Dirk Brandewie <[email protected]>

commit adacdf3f2b8e65aa441613cf61c4f598e9042690 upstream.

Commit fcb6a15c (intel_pstate: Take core C0 time into account for core
busy calculation) introduced a regression referenced below.  The issue
with "lockup" after suspend that this commit was addressing is now dealt
with in the suspend path.

Fixes: fcb6a15c2e7e (intel_pstate: Take core C0 time into account for core busy 
calculation)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=66581
Link: https://bugzilla.kernel.org/show_bug.cgi?id=75121
Reported-by: Doug Smythies <[email protected]>
Signed-off-by: Dirk Brandewie <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/cpufreq/intel_pstate.c |   13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -59,7 +59,6 @@ struct sample {
        int32_t core_pct_busy;
        u64 aperf;
        u64 mperf;
-       unsigned long long tsc;
        int freq;
 };
 
@@ -100,7 +99,6 @@ struct cpudata {
 
        u64     prev_aperf;
        u64     prev_mperf;
-       unsigned long long prev_tsc;
        struct sample sample;
 };
 
@@ -561,46 +559,37 @@ static inline void intel_pstate_calc_bus
                                        struct sample *sample)
 {
        int32_t core_pct;
-       int32_t c0_pct;
 
        core_pct = div_fp(int_tofp((sample->aperf)),
                        int_tofp((sample->mperf)));
        core_pct = mul_fp(core_pct, int_tofp(100));
        FP_ROUNDUP(core_pct);
 
-       c0_pct = div_fp(int_tofp(sample->mperf), int_tofp(sample->tsc));
-
        sample->freq = fp_toint(
                mul_fp(int_tofp(cpu->pstate.max_pstate * 1000), core_pct));
 
-       sample->core_pct_busy = mul_fp(core_pct, c0_pct);
+       sample->core_pct_busy = core_pct;
 }
 
 static inline void intel_pstate_sample(struct cpudata *cpu)
 {
        u64 aperf, mperf;
-       unsigned long long tsc;
 
        rdmsrl(MSR_IA32_APERF, aperf);
        rdmsrl(MSR_IA32_MPERF, mperf);
-       tsc = native_read_tsc();
 
        aperf = aperf >> FRAC_BITS;
        mperf = mperf >> FRAC_BITS;
-       tsc = tsc >> FRAC_BITS;
 
        cpu->sample.aperf = aperf;
        cpu->sample.mperf = mperf;
-       cpu->sample.tsc = tsc;
        cpu->sample.aperf -= cpu->prev_aperf;
        cpu->sample.mperf -= cpu->prev_mperf;
-       cpu->sample.tsc -= cpu->prev_tsc;
 
        intel_pstate_calc_busy(cpu, &cpu->sample);
 
        cpu->prev_aperf = aperf;
        cpu->prev_mperf = mperf;
-       cpu->prev_tsc = tsc;
 }
 
 static inline void intel_pstate_set_sample_time(struct cpudata *cpu)


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