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authorHoan Tran <hotran@apm.com>2016-10-13 10:33:35 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-10-13 23:10:41 +0200
commitc197d758036d8c77923ae3f88571cf198283107e (patch)
tree9dea7912efc8aa2036eec6c157403643a3e07f5a /drivers
parentabb6627910a1e783c8e034b35b7c80e5e7f98f41 (diff)
downloadlinux-c197d758036d8c77923ae3f88571cf198283107e.tar.bz2
cpufreq: CPPC: Correct desired_perf calculation
The desired_perf is an abstract performance number. Its value should be in the range of [lowest perf, highest perf] of CPPC. The correct calculation is desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz And cppc_cpufreq_set_target() returns if desired_perf is exactly the same with the old perf. Signed-off-by: Hoan Tran <hotran@apm.com> Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpufreq/cppc_cpufreq.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 99db4227ae38..f7e98fc077c1 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -80,11 +80,17 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
{
struct cpudata *cpu;
struct cpufreq_freqs freqs;
+ u32 desired_perf;
int ret = 0;
cpu = all_cpu_data[policy->cpu];
- cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
+ desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
+ /* Return if it is exactly the same perf */
+ if (desired_perf == cpu->perf_ctrls.desired_perf)
+ return ret;
+
+ cpu->perf_ctrls.desired_perf = desired_perf;
freqs.old = policy->cur;
freqs.new = target_freq;