{"action":"created","issue":{"url":"https://api.github.com/repos/raspberrypi/linux/issues/1320","repository_url":"https://api.github.com/repos/raspberrypi/linux","labels_url":"https://api.github.com/repos/raspberrypi/linux/issues/1320/labels{/name}","comments_url":"https://api.github.com/repos/raspberrypi/linux/issues/1320/comments","events_url":"https://api.github.com/repos/raspberrypi/linux/issues/1320/events","html_url":"https://github.com/raspberrypi/linux/issues/1320","id":138157301,"number":1320,"title":"DVFS/cpufreq appears to be broken on Raspberry Pi 3","user":{"login":"lgeek","id":101596,"avatar_url":"https://avatars.githubusercontent.com/u/101596?v=3","gravatar_id":"","url":"https://api.github.com/users/lgeek","html_url":"https://github.com/lgeek","followers_url":"https://api.github.com/users/lgeek/followers","following_url":"https://api.github.com/users/lgeek/following{/other_user}","gists_url":"https://api.github.com/users/lgeek/gists{/gist_id}","starred_url":"https://api.github.com/users/lgeek/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/lgeek/subscriptions","organizations_url":"https://api.github.com/users/lgeek/orgs","repos_url":"https://api.github.com/users/lgeek/repos","events_url":"https://api.github.com/users/lgeek/events{/privacy}","received_events_url":"https://api.github.com/users/lgeek/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":4,"created_at":"2016-03-03T11:53:17Z","updated_at":"2016-03-03T13:23:05Z","closed_at":null,"body":"Hi,\r\n\r\nI've tried and failed to replicate Gareth's excessive overheating test (https://www.reddit.com/r/raspberry_pi/comments/48lhot/raspberry_pi_family_thermal_analysis_thermal/). The SoC on my board stays around 60-70 degrees.\r\n\r\nHowerver, I think I've figured out why: DVFS/cpufreq appears to be broken on my board. Even if set to the performance governor, or to the userspace governor with the frequency set at 1.2GHz, if I poll /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq, it will only show 1200 MHz very rarely, maybe once in 20-40 samples and 600 MHz most of the time. The behaviour is identical if I try to set the frequency to 600 MHz, it still goes up to 1200 MHz from time to time. This is happening both when idle and when under load and at any operating temperatures (even perfectly reasonable ones like 40 degrees).\r\n\r\nI'm not really sure what performance I should expect from benchmarks, but I'm getting very high measurement noise, consistent with DVFS randomly switching the operating frequency while short benchmarks are running.\r\n\r\nI've tried both a kernel I've built from this repository and the one distributed with Raspbian."},"comment":{"url":"https://api.github.com/repos/raspberrypi/linux/issues/comments/191759583","html_url":"https://github.com/raspberrypi/linux/issues/1320#issuecomment-191759583","issue_url":"https://api.github.com/repos/raspberrypi/linux/issues/1320","id":191759583,"user":{"login":"clivem","id":1668152,"avatar_url":"https://avatars.githubusercontent.com/u/1668152?v=3","gravatar_id":"","url":"https://api.github.com/users/clivem","html_url":"https://github.com/clivem","followers_url":"https://api.github.com/users/clivem/followers","following_url":"https://api.github.com/users/clivem/following{/other_user}","gists_url":"https://api.github.com/users/clivem/gists{/gist_id}","starred_url":"https://api.github.com/users/clivem/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/clivem/subscriptions","organizations_url":"https://api.github.com/users/clivem/orgs","repos_url":"https://api.github.com/users/clivem/repos","events_url":"https://api.github.com/users/clivem/events{/privacy}","received_events_url":"https://api.github.com/users/clivem/received_events","type":"User","site_admin":false},"created_at":"2016-03-03T13:23:05Z","updated_at":"2016-03-03T13:23:05Z","body":"@lgeek If wanting accurate arm core speed, you want to be getting it from the firmware, not the kernel. It doesn't get reported back to the kernel when the firmware is throttling. \"cat ......../cpuinfo_cur_freq\" will still be showing 1.2G, even when firmware has throttled back to 900M. Not that this is your problem, just saying."}}