On 31 July 2014 09:09, Aaron Lu <aaron.lu@xxxxxxxxx> wrote: > Please add acpi_backlight=vendor to kernel cmdline and see if that makes > the backlight work. What it does is to tell ACPI video module not to > create the acpi_videoX sysfs interface and let's see if X server will > pick up the intel_backlight one. Adding acpi_backlight=vendor to the kernel cmdline results in the brightness controls not working from first boot, not just after a suspend. Detailed test results: After fresh boot into 3.16-rc with acpi_backlight=vendor added to the kernel cmdline ls -l /sys/class/backlight total 0 lrwxrwxrwx 1 root root 0 Jul 31 21:38 intel_backlight -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight lrwxrwxrwx 1 root root 0 Jul 31 21:38 toshiba -> ../../devices/LNXSYSTM:00/LNXSYBUS:00/TOS6208:00/backlight/toshiba Attempts to adjust brightness via user interfaces (system settings and function keys) fail to change brightness. It remains possible to adjust brightness by directly writing to /sys/class/backlight/intel_backlight/brightness but, as before, not by writing to /sys/class/backlight/toshiba/brightness. After suspend and resume same test results. Regards, John -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
