Ubuntu
linux package

  1. Bug #935778
  2. Comment #9

Comment 9 for bug 935778

Revision history for this message
jowi (jowi) wrote : Re: Toshiba R840 - brightness controls work on first boot, but do nothing after suspend/resume

My Tecra R840 shows the exact symptoms as described before. I'm on precise with all current updates (Linux brahms 3.2.0-20-generic #32-Ubuntu SMP Thu Mar 22 02:22:46 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux).

With and without Seth' patched driver from #8 (Thanks, Seth, for your fine work. I already appreciated your alps patch while on oneiric.) I'm able to manipulate the brightness files of all three interfaces under /sys/class/backlight (acpi_video0, intel_backlight, toshiba). Before suspend the display respects all these changes and sets the brightness accordingly. After resume changes in acpi_video0 and toshiba are ignored, changes in intel_backlight still effectively change the brightness of the display. This is what I currently use as workaround by means of the little script attached, which translates the different values of intel_backlight and acpi_video0/toshiba.

With Seth' driver installed my Tecra freezes on suspend or the backlight stays off on resume. Before suspend I recognized that changing the brightness via Fn-F6/7 uses all 8 levels, whereas without the patched driver one keystroke always takes two at a time. AFAICT the logs don't give any hint.