From 8478f53946f01b8365a206ac58a2640e3e408fb2 Mon Sep 17 00:00:00 2001 From: Prarit Bhargava Date: Fri, 20 Nov 2015 18:47:56 -0500 Subject: cpufreq: intel_pstate: Fix limits->max_policy_pct rounding error I have a Intel (6,63) processor with a "marketing" frequency (from /proc/cpuinfo) of 2100MHz, and a max turbo frequency of 2600MHz. I can execute cpupower frequency-set -g powersave --min 1200MHz --max 2100MHz and the max_freq_pct is set to 80. When adding load to the system I noticed that the cpu frequency only reached 2000MHZ and not 2100MHz as expected. This is because limits->max_policy_pct is calculated as 2100 * 100 /2600 = 80.7 and is rounded down to 80 when it should be rounded up to 81. This patch adds a DIV_ROUND_UP() which will return the correct value. Signed-off-by: Prarit Bhargava Acked-by: Srinivas Pandruvada Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/cpufreq/intel_pstate.c') diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 001a532..eb75053 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1108,7 +1108,8 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) limits = &powersave_limits; limits->min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; limits->min_policy_pct = clamp_t(int, limits->min_policy_pct, 0 , 100); - limits->max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; + limits->max_policy_pct = DIV_ROUND_UP(policy->max * 100, + policy->cpuinfo.max_freq); limits->max_policy_pct = clamp_t(int, limits->max_policy_pct, 0 , 100); /* Normalize user input to [min_policy_pct, max_policy_pct] */ -- cgit v1.1