<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO --- - [regression] Backlight too dim to use from kernel 3.14 and systemd error" href="https://bugs.freedesktop.org/show_bug.cgi?id=78200#c10">Comment # 10</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO --- - [regression] Backlight too dim to use from kernel 3.14 and systemd error" href="https://bugs.freedesktop.org/show_bug.cgi?id=78200">bug 78200</a> from <a class="email" href="mailto:jani.nikula@intel.com" title="Jani Nikula <jani.nikula@intel.com>"> Jani Nikula</a> <pre>(In reply to <a href="show_bug.cgi?id=78200#c0">comment #0</a>) > I reverted to kernel 3.13.7-1-ARCH and the screen brightness seemed normal > but an investigation of the systemd journal showed there were errors that > are relevant to this issue: > > May 02 17:08:49 samsung1 systemd[1]: Starting Load/Save Screen Backlight > Brightness of backlight:intel_backlight... > May 02 17:08:49 samsung1 systemd-backlight[191]: Failed to write system > attribute: Invalid argument > May 02 17:08:49 samsung1 systemd[1]: > systemd-backlight@backlight:intel_backlight.service: main process exited, > code=exited, status=1/FAI > May 02 17:08:49 samsung1 systemd[1]: Failed to start Load/Save Screen > Backlight Brightness of backlight:intel_backlight. > May 02 17:08:49 samsung1 systemd[1]: Unit > systemd-backlight@backlight:intel_backlight.service entered failed state. Looking at the systemd source, it seems to me this happens because there's a too high saved value for backlight. I don't know how it got there, but the clamping and error handling don't take this into account. Try removing, uh, the relevant looking files from /var/lib/systemd/backlight/ - there should be file(s) containing the saved values, named with escaped names of the interfaces. If that doesn't help, try systemd.restore_state=0 on the kernel command line. There may be a way to pass that to systemd directly too, but I'm rather clueless about systemd details. Let us know if that helps. Finally, please try 3.15-rc kernels; I think there's a fix or two there that haven't propagated to stable kernels yet.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>