I just dist-upgraded again, and with 4.8.0-14 my brightness keys work again (bug 1626429). Under i3 (no unity-settings-daemon), I get a tame and immediate reaction:
UDEV [38372.886325] change /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight) ACTION=change DEVPATH=/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 ID_PATH=pci-0000:00:02.0 ID_PATH_TAG=pci-0000_00_02_0 SEQNUM=2735 SOURCE=hotkey SUBSYSTEM=backlight SYSTEMD_WANTS=systemd-backlight@backlight:acpi_video0.service TAGS=:systemd: USEC_INITIALIZED=9377712 21:07:21 fork 1298 parent /lib/systemd/systemd-udevd 21:07:21 fork 25614 child /lib/systemd/systemd-udevd 21:07:21 exit 25614 0 0.002 /lib/systemd/systemd-udevd which matches the one uevent, but there is no userspace helper involved. Brightness change still works as it's hardwired into the driver. This proves that with just kernel and udev rules there is no delay and waste. Under unity, with unity-settings-daemon, I now confirm the flurry of userspace action. The main pain point is the pkexec in pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --get- brightness as that starts a full new PAM session, including systemd --user and other expensive stuff. Our /etc/pam.d/polkit-1 pulls in "common- session"; when changing this to "common-session-noninteractive" it becomes muuuch cheaper, but this would again be wrong for cases where we actually do want to run a new session for whatever we run there -- I'm trying to think about cases where this would break. I. e. should pk-exec behave more like "su" or "su -". It would probably be best to grep the archive for usage of pk-exec, review whether any of it requires an interactive PAM session, and if not switch it to noninteractive. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1626651 Title: brightness keys are handled slower in Yakkety than Xenial Status in policykit-1 package in Ubuntu: Triaged Status in unity-settings-daemon package in Ubuntu: Triaged Bug description: I've noticed on Lenovo X220 and X230 laptops that pressing brightness keys on Yakkety seems less responsive and slower than Xenial. I ran forkstat on Xenial and just observed udev being forked off: Xenial: $ sudo forkstat Time Event PID Info Duration Process 17:37:35 fork 273 parent /lib/systemd/systemd-udevd 17:37:35 fork 1977 child /lib/systemd/systemd-udevd 17:37:35 exit 1977 0 0.008 /lib/systemd/systemd-udevd Whereas on Yakkety, there is far more activity: Time Event PID Info Duration Process 16:35:34 fork 2626 parent update-notifier 16:35:34 fork 2645 child update-notifier 16:35:34 exec 2645 /usr/bin/python3 /usr/share/apport/apport-checkreports 16:35:34 exit 2645 256 0.221 /usr/bin/python3 /usr/share/apport/apport-checkreports 16:35:34 fork 2626 parent update-notifier 16:35:34 fork 2646 child update-notifier 16:35:34 exec 2646 /usr/bin/python3 /usr/share/apport/apport-checkreports --system 16:35:34 exit 2646 256 0.188 /usr/bin/python3 /usr/share/apport/apport-checkreports --system 16:35:36 fork 1576 parent /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 fork 2647 child /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 exec 2647 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness 16:35:36 exit 2647 0 0.008 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness 16:35:36 fork 1576 parent /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 fork 2648 child /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 exec 2648 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness 16:35:36 exit 2648 0 0.006 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness 16:35:36 fork 1576 parent /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 fork 2649 child /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 exec 2649 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness 16:35:36 exit 2649 0 0.007 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness 16:35:36 fork 1576 parent /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 fork 2650 child /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 exec 2650 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness 16:35:36 exit 2650 0 0.006 /usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness 16:35:36 fork 1576 parent /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 fork 2651 child /usr/lib/unity-settings-daemon/unity-settings-daemon 16:35:36 exec 2651 pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 clone 2651 parent pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 clone 2652 thread pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 clone 2651 parent pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 clone 2653 thread pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 fork 1 parent /sbin/init splash 16:35:36 fork 2654 child /sbin/init splash Time Event PID Info Duration Process 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2655 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2656 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2657 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2658 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2659 child /lib/systemd/systemd-udevd 16:35:36 exit 2659 0 0.005 /lib/systemd/systemd-udevd 16:35:36 exit 2658 0 0.006 /lib/systemd/systemd-udevd 16:35:36 exit 2657 0 0.007 /lib/systemd/systemd-udevd 16:35:36 exit 2656 0 0.008 /lib/systemd/systemd-udevd 16:35:36 exit 2655 0 0.008 /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2660 child /lib/systemd/systemd-udevd 16:35:36 exit 2660 0 0.001 /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2661 child /lib/systemd/systemd-udevd 16:35:36 exit 2661 0 0.002 /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2662 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2663 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2664 child /lib/systemd/systemd-udevd 16:35:36 fork 2654 parent /sbin/init splash 16:35:36 fork 2665 child (systemd) 16:35:36 exec 2654 /lib/systemd/systemd --user 16:35:36 exit 2662 0 0.010 /lib/systemd/systemd-udevd 16:35:36 exit 2664 0 0.007 /lib/systemd/systemd-udevd Time Event PID Info Duration Process 16:35:36 exit 2663 0 0.009 /lib/systemd/systemd-udevd 16:35:36 fork 2654 parent /lib/systemd/systemd --user 16:35:36 fork 2666 child /lib/systemd/systemd --user 16:35:36 exit 2666 0 0.001 /lib/systemd/systemd --user 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2667 child /lib/systemd/systemd-udevd 16:35:36 exit 2667 0 0.003 /lib/systemd/systemd-udevd 16:35:36 fork 2654 parent /lib/systemd/systemd --user 16:35:36 fork 2668 child /lib/systemd/systemd --user 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2669 child /lib/systemd/systemd-udevd 16:35:36 exit 2669 0 0.002 /lib/systemd/systemd-udevd 16:35:36 exec 2668 /bin/systemctl --user set-environment DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/0/bus 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2670 child /lib/systemd/systemd-udevd 16:35:36 exit 2670 0 0.001 /lib/systemd/systemd-udevd 16:35:36 exit 2668 0 0.009 /bin/systemctl --user set-environment DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/0/bus 16:35:36 fork 2 parent [kthreadd] 16:35:36 fork 2671 child [kworker/u16:4] 16:35:36 exec 2671 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service/dbus.socket] 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2672 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2673 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2674 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2675 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2676 child /lib/systemd/systemd-udevd 16:35:36 exit 2671 0 0.005 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service/dbus.socket] 16:35:36 fork 233 parent /lib/systemd/systemd-udevd Time Event PID Info Duration Process 16:35:36 fork 2677 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2678 child /lib/systemd/systemd-udevd 16:35:36 exit 2653 0 0.126 pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 exit 2652 0 0.126 pkexec /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 exec 2651 /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 exit 2673 0 0.013 /lib/systemd/systemd-udevd 16:35:36 exit 2672 0 0.013 /lib/systemd/systemd-udevd 16:35:36 exit 2678 0 0.011 /lib/systemd/systemd-udevd 16:35:36 exit 2675 0 0.013 /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2679 child /lib/systemd/systemd-udevd 16:35:36 exit 2674 0 0.020 /lib/systemd/systemd-udevd 16:35:36 exit 2651 0 0.146 /usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250 16:35:36 fork 2 parent [kthreadd] 16:35:36 fork 2680 child [kworker/u16:5] 16:35:36 exec 2680 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/session-2.scope] 16:35:36 exit 2676 0 0.022 /lib/systemd/systemd-udevd 16:35:36 exit 2679 0 0.003 /lib/systemd/systemd-udevd 16:35:36 exit 2677 0 0.022 /lib/systemd/systemd-udevd 16:35:36 exit 2680 0 0.003 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/session-2.scope] 16:35:36 fork 2654 parent /lib/systemd/systemd --user 16:35:36 fork 2681 child /lib/systemd/systemd --user 16:35:36 exec 2681 /bin/kill -s 58 2654 16:35:36 exit 2681 0 0.200 /bin/kill -s 58 2654 16:35:36 fork 2 parent [kthreadd] 16:35:36 fork 2682 child [kworker/u16:5] 16:35:36 exec 2682 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service/systemd-exit.service] 16:35:36 exit 2654 0 0.294 /lib/systemd/systemd --user 16:35:36 exit 2682 0 0.004 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service/systemd-exit.service] 16:35:36 exit 2665 9 0.272 (systemd) 16:35:36 fork 2 parent [kthreadd] Time Event PID Info Duration Process 16:35:36 fork 2683 child [kworker/u16:5] 16:35:36 exec 2683 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service/init.scope] 16:35:36 fork 2 parent [kthreadd] 16:35:36 fork 2684 child [kworker/u16:4] 16:35:36 fork 2 parent [kthreadd] 16:35:36 fork 2685 child [systemd-cgroups] 16:35:36 exec 2684 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service] 16:35:36 exec 2685 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice] 16:35:36 exit 2683 0 0.005 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service/init.scope] 16:35:36 exit 2685 0 0.005 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice] 16:35:36 exit 2684 0 0.007 [/lib/systemd/systemd-cgroups-agent /user.slice/user-0.slice/user@0.service] 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2686 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2687 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2688 child /lib/systemd/systemd-udevd 16:35:36 fork 233 parent /lib/systemd/systemd-udevd 16:35:36 fork 2689 child /lib/systemd/systemd-udevd 16:35:36 exit 2687 0 0.014 /lib/systemd/systemd-udevd 16:35:36 exit 2689 0 0.013 /lib/systemd/systemd-udevd 16:35:36 exit 2686 0 0.015 /lib/systemd/systemd-udevd 16:35:36 exit 2688 0 0.015 /lib/systemd/systemd-udevd I suspect some of this overhead explains the slower responsive feel to the brightness buttons. Anyhow, seems like a bit of an overkill for all these processes to be running especially compared to Xenial. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/policykit-1/+bug/1626651/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
