From: Hoan Tran Date: Thu, 13 Oct 2016 17:33:35 +0000 (-0700) Subject: cpufreq: CPPC: Correct desired_perf calculation X-Git-Tag: v4.9-rc1~19^2^2 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=c197d758036d8c77923ae3f88571cf198283107e 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 Reviewed-by: Prashanth Prakash Signed-off-by: Rafael J. Wysocki --- 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;