** Description changed: + SRU Justification: + + Impact: upon boot, frequency scaling is not working. + + Fix: Apply the patches, recompile and reboot. + + Testcase: Try booting a beaglebone with and without a patched + kernel. + + With this series applied there should be: + + ubuntu@beaglebone:~$ ls -la /sys/devices/system/cpu/cpu0/cpufreq/ + total 0 + drwxr-xr-x 3 root root 0 May 22 07:03 . + drwxr-xr-x 5 root root 0 May 22 07:03 .. + -r--r--r-- 1 root root 4096 May 22 07:03 affected_cpus + -r-------- 1 root root 4096 May 22 07:03 cpuinfo_cur_freq + -r--r--r-- 1 root root 4096 May 22 07:03 cpuinfo_max_freq + -r--r--r-- 1 root root 4096 May 22 07:03 cpuinfo_min_freq + -r--r--r-- 1 root root 4096 May 22 07:03 cpuinfo_transition_latency + -r--r--r-- 1 root root 4096 May 22 07:03 related_cpus + -r--r--r-- 1 root root 4096 May 22 07:03 scaling_available_frequencies + -r--r--r-- 1 root root 4096 May 22 07:03 scaling_available_governors + -r--r--r-- 1 root root 4096 May 22 07:03 scaling_cur_freq + -r--r--r-- 1 root root 4096 May 22 07:03 scaling_driver + -rw-r--r-- 1 root root 4096 May 22 04:43 scaling_governor + -rw-r--r-- 1 root root 4096 May 22 07:03 scaling_max_freq + -rw-r--r-- 1 root root 4096 May 22 07:03 scaling_min_freq + -rw-r--r-- 1 root root 4096 May 22 07:03 scaling_setspeed + drwxr-xr-x 2 root root 0 May 22 07:03 stats + ubuntu@beaglebone:~$ + + With an unpatched kernel, until the cpufreq module is loaded, that + directory doesn't exist. + + ... + While cpufreq support on armhf is available for a while, if support is compiled as a kernel module, the corresponding module doesn't autoload by default, and thus frequency scaling is not active upon boot until a user manually load it (or until /etc/modules is modified to forcibly load it). While in Trusty cpufreq was built-in on armhf, starting with Utopic we made support available as a kernel module, making people think that cpufreq was either broken or missing in their new kernels. To fix it, revert back that decision and make cpufreq compiled-in again on armhf - it affects Utopic and Vivid kernels.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1457781 Title: armhf: cpufreq doesn't autoload by default To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1457781/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs