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authorLinus Torvalds <torvalds@linux-foundation.org>2018-05-04 05:44:50 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2018-05-04 05:44:50 -1000
commit54c6fd566bb887e2c01d0db00ac83a1f1e8fd0d8 (patch)
tree7c4a261a4641e61d153e219ef0a3d96319251dae
parentc33ede14337a3a486f9529f27907a2f964bc94e8 (diff)
parentd4f3388afd488ed15368fa7413b8bd6d1f98bb1d (diff)
downloadlinux-stericsson-54c6fd566bb887e2c01d0db00ac83a1f1e8fd0d8.tar.gz
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.c46
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) {