From 3baa976ae644f76f5cdb5be0fb26754c3bfb32cb Mon Sep 17 00:00:00 2001 From: Xiaoguang Chen Date: Thu, 7 Nov 2013 10:28:50 +0800 Subject: [PATCH] cpufreq: conservative: fix requested_freq reduction issue When decreasing frequency, requested_freq may be less than freq_target, So requested_freq minus freq_target may be negative, But reqested_freq's unit is unsigned int, then the negative result will be one larger interger which may be even higher than requested_freq. This patch is to fix such issue. when result becomes negative, set requested_freq as the min value of policy. Signed-off-by: Xiaoguang Chen Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq_conservative.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c index f62d822048e6..218460fcd2e4 100644 --- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -80,13 +80,18 @@ static void cs_check_cpu(int cpu, unsigned int load) /* Check for frequency decrease */ if (load < cs_tuners->down_threshold) { + unsigned int freq_target; /* * if we cannot reduce the frequency anymore, break out early */ if (policy->cur == policy->min) return; - dbs_info->requested_freq -= get_freq_target(cs_tuners, policy); + freq_target = get_freq_target(cs_tuners, policy); + if (dbs_info->requested_freq > freq_target) + dbs_info->requested_freq -= freq_target; + else + dbs_info->requested_freq = policy->min; __cpufreq_driver_target(policy, dbs_info->requested_freq, CPUFREQ_RELATION_L); -- 2.20.1