[PATCH 3.14 64/78] intel_pstate: Remove C0 tracking

Greg Kroah-Hartman
2014-06-09T22:46:43Z

From: Dirk Brandewie <dirk.j.brandewie@intel.com>

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 <dsmythies@telus.net>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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)