On 30 July 2014 09:32, Aaron Lu <aaron.lu@xxxxxxxxx> wrote: > Does the other interface work after resume? I mean the intel_backlight > and the toshiba one? The intel-backlight interface works but the toshiba one does not work. Below is my detailed test actions and results: Fresh boot in v3.16-rc ====================== sudo su cat /sys/class/backlight/intel_backlight/brightness 4539 cat /sys/class/backlight/toshiba/brightness 7 cat /sys/class/backlight/acpi_video0/brightness 7 Operate brightness control downwards via system settings. Screen dims: cat /sys/class/backlight/intel_backlight/brightness 3844 Restored brightness control to full via system settings. Screen brightens: cat /sys/class/backlight/intel_backlight/brightness 4539 Suspend and resume ================== cat /sys/class/backlight/intel_backlight/brightness 4539 cat /sys/class/backlight/toshiba/brightness 7 cat /sys/class/backlight/acpi_video0/brightness 7 TEST operating brightness controls via user interface: Operate brightness control downwards via system settings. No change to screen brightness: cat /sys/class/backlight/intel_backlight/brightness 4539 Restored brightness control to full via system settings. No change to screen brightness: cat /sys/class/backlight/intel_backlight/brightness 4539 TEST setting directly via sysfs: echo 3844 > /sys/class/backlight/intel_backlight/brightness screen goes dimmer. cat /sys/class/backlight/intel_backlight/brightness 3844 echo 4539 > /sys/class/backlight/intel_backlight/brightness Screen goes brighter. cat /sys/class/backlight/intel_backlight/brightness 4539 BUT: echo 2 > /sys/class/backlight/toshiba/brightness no change to screen brightness. cat /sys/class/backlight/intel_backlight/brightness 4539 cat /sys/class/backlight/toshiba/brightness 2 echo 7 > /sys/class/backlight/toshiba/brightness cat /sys/class/backlight/toshiba/brightness 7 AND: echo 2 > /sys/class/backlight/acpi_video0/brightness no change to screen brightness. cat /sys/class/backlight/acpi_video0/brightness 2 cat /sys/class/backlight/intel_backlight/brightness 4539 echo 7 > /sys/class/backlight/acpi_video0/brightness cat /sys/class/backlight/acpi_video0/brightness 7 NOTE ALSO: ========== On previous test after suspend and resume screen comes up dim: cat /sys/class/backlight/intel_backlight/brightness 249 cat /sys/class/backlight/toshiba/brightness 7 cat /sys/class/backlight/acpi_video0/brightness 7 I'm not sure what it is that determines whether screen comes up dimmed after suspend and resume. Seems to be related to whether power is plugged in and/or screen has dimmed automatically because of computer auto-suspending after in-activity. Thanks for your help. 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
