If the screen is on and I run "xset dpms force off", I have to manually set bl_power to 0 in order to turn the screen on again. Here some data I collected. * If the screen is off and set dpms to off, I get: cat /sys/class/drm/card0/card0-DP-1/dpms On cat /sys/class/drm/card0/card0-eDP-1/dpms Off cat /sys/class/backlight/intel_backlight/bl_power 4 cat /sys/class/backlight/intel_backlight/brightness 0 * If I try to turn the screen on by pressing any key, I get: cat /sys/class/drm/card0/card0-DP-1/dpms On cat /sys/class/drm/card0/card0-eDP-1/dpms On cat /sys/class/backlight/intel_backlight/bl_power 1 cat /sys/class/backlight/intel_backlight/brightness 94 * At this point, to turn the screen on, I have to toggle bl_power. lspci: 00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)
I'm sorry, in the first point I meant to write: "If the screen is on and set dpms to off, I get:" instead of "If the screen is off and set dpms to off, I get:"
commit 7ecc778691c452285f754743a93a46fa1d3da52f Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Tue Nov 4 10:36:26 2014 +0000 backlight: bl_power uses 0 for on and 4 for off The backlight/bl_power file didn't obey the obvious semantics, but instead operates using some interesting framebuffer API. Oh well. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Thanks for pointing the fix, I haven't seen it.