From 2e6ae5400b468f9a797f57ad8926ff894468b122 Mon Sep 17 00:00:00 2001 From: Andreas Herrmann Date: Fri, 22 Jul 2016 17:14:11 +0200 Subject: [PATCH] Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency" This reverts commit 0beb240dc0268e71c1fdad975adf5b15b5379b6a. Using a v4.7-rc7 kernel on a HP ProLiant triggered following messages pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor The last line was shown for each CPU in the system. Testing v4.5 (where commit 0beb240d was integrated) triggered similar messages. Same behaviour on a 2nd HP Proliant system. So commit 0beb240dc (cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency) causes the system to use performance governor which, I guess, was not the intention of the patch. Enabling debug output in pcc-cpufreq provides following verbose output: pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1200 MHz, 2800 MHz pcc_get_offset: for CPU 0: pcc_cpu_data input_offset: 0x44, pcc_cpu_data output_offset: 0x48 init: policy->max is 2800000, policy->min is 1200000 get: get_freq for CPU 0 get: SUCCESS: (virtual) output_offset for cpu 0 is 0xffffc9000d7c0048, contains a value of: 0xff06. Speed is: 168000 MHz cpufreq: ondemand governor failed, too long transition latency of HW, fallback to performance governor target: CPU 0 should go to target freq: 2800000 (virtual) input_offset is 0xffffc9000d7c0044 target: was SUCCESSFUL for cpu 0 I am asking to revert 0beb240dc to re-enable usage of ondemand governor with pcc-cpufreq. Fixes: 0beb240dc (cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency) CC: # 4.5+ Signed-off-by: Andreas Herrmann Signed-off-by: Rafael J. Wysocki --- Documentation/cpu-freq/pcc-cpufreq.txt | 4 ++-- drivers/cpufreq/pcc-cpufreq.c | 2 -- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/Documentation/cpu-freq/pcc-cpufreq.txt b/Documentation/cpu-freq/pcc-cpufreq.txt index 0a94224ad2965..9e3c3b33514c6 100644 --- a/Documentation/cpu-freq/pcc-cpufreq.txt +++ b/Documentation/cpu-freq/pcc-cpufreq.txt @@ -159,8 +159,8 @@ to be strictly associated with a P-state. 2.2 cpuinfo_transition_latency: ------------------------------- -The cpuinfo_transition_latency field is CPUFREQ_ETERNAL. The PCC specification -does not include a field to expose this value currently. +The cpuinfo_transition_latency field is 0. The PCC specification does +not include a field to expose this value currently. 2.3 cpuinfo_cur_freq: --------------------- diff --git a/drivers/cpufreq/pcc-cpufreq.c b/drivers/cpufreq/pcc-cpufreq.c index a7ecb9a84c159..3f0ce2ae35ee4 100644 --- a/drivers/cpufreq/pcc-cpufreq.c +++ b/drivers/cpufreq/pcc-cpufreq.c @@ -555,8 +555,6 @@ static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy) policy->min = policy->cpuinfo.min_freq = ioread32(&pcch_hdr->minimum_frequency) * 1000; - policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; - pr_debug("init: policy->max is %d, policy->min is %d\n", policy->max, policy->min); out: -- 2.39.5