summaryrefslogtreecommitdiff
path: root/Documentation/cpu-freq
diff options
context:
space:
mode:
authorAndreas Herrmann <aherrmann@suse.com>2016-07-22 18:14:11 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-07-23 00:51:06 +0300
commitda7d3abe1c9e5ebac2cf86f97e9e89888a5e2094 (patch)
tree6eb238c4de38b21cf594ed3f2a18ce11fd70a2e2 /Documentation/cpu-freq
parentae2c1ca686d4b80258a442fa7f3edc71fd0ebb39 (diff)
downloadlinux-da7d3abe1c9e5ebac2cf86f97e9e89888a5e2094.tar.xz
Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"
This reverts commit 790d849bf811a8ab5d4cd2cce0f6fda92f6aebf2. 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 790d849b was integrated) triggered similar messages. Same behaviour on a 2nd HP Proliant system. So commit 790d849bf (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 790d849bf to re-enable usage of ondemand governor with pcc-cpufreq. Fixes: 790d849bf (cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency) CC: <stable@vger.kernel.org> # 4.5+ Signed-off-by: Andreas Herrmann <aherrmann@suse.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/cpu-freq')
-rw-r--r--Documentation/cpu-freq/pcc-cpufreq.txt4
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/cpu-freq/pcc-cpufreq.txt b/Documentation/cpu-freq/pcc-cpufreq.txt
index 0a94224ad296..9e3c3b33514c 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:
---------------------