intel_pstate: Remove C0 tracking

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 <dsmythies@telus.net>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index eab8ccf..e573544 100644 (file)
--- 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_busy(struct cpudata *cpu,
                                        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)