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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-05-04 18:44:50 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-05-04 18:44:50 +0300 |
| commit | 54c6fd566bb887e2c01d0db00ac83a1f1e8fd0d8 (patch) | |
| tree | 7c4a261a4641e61d153e219ef0a3d96319251dae | |
| parent | c33ede14337a3a486f9529f27907a2f964bc94e8 (diff) | |
| parent | d4f3388afd488ed15368fa7413b8bd6d1f98bb1d (diff) | |
| download | linux-54c6fd566bb887e2c01d0db00ac83a1f1e8fd0d8.tar.xz | |
Merge tag 'pm-4.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fix from Rafael Wysocki:
"This fixes a regression from the 4.14 cycle in the CPPC cpufreq driver
causing it to use an incorrect transition delay value which leads to a
very high rate of frequency change requests when the schedutil
governor is in use (Prashanth Prakash)"
* tag 'pm-4.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq / CPPC: Set platform specific transition_delay_us
| -rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index bc5fc1630876..b15115a48775 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -126,6 +126,49 @@ static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy) cpu->perf_caps.lowest_perf, cpu_num, ret); } +/* + * The PCC subspace describes the rate at which platform can accept commands + * on the shared PCC channel (including READs which do not count towards freq + * trasition requests), so ideally we need to use the PCC values as a fallback + * if we don't have a platform specific transition_delay_us + */ +#ifdef CONFIG_ARM64 +#include <asm/cputype.h> + +static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu) +{ + unsigned long implementor = read_cpuid_implementor(); + unsigned long part_num = read_cpuid_part_number(); + unsigned int delay_us = 0; + + switch (implementor) { + case ARM_CPU_IMP_QCOM: + switch (part_num) { + case QCOM_CPU_PART_FALKOR_V1: + case QCOM_CPU_PART_FALKOR: + delay_us = 10000; + break; + default: + delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC; + break; + } + break; + default: + delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC; + break; + } + + return delay_us; +} + +#else + +static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu) +{ + return cppc_get_transition_latency(cpu) / NSEC_PER_USEC; +} +#endif + static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) { struct cppc_cpudata *cpu; @@ -162,8 +205,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) cpu->perf_caps.highest_perf; policy->cpuinfo.max_freq = cppc_dmi_max_khz; - policy->transition_delay_us = cppc_get_transition_latency(cpu_num) / - NSEC_PER_USEC; + policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num); policy->shared_type = cpu->shared_type; if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) { |