Created attachment 113997 [details] $ journalctl -b -k Starting the Lenovo X60t (DMI: LENOVO 636338U/636338U, BIOS 7JET23WW (1.08 ) 04/18/2007) 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03) with an external screen attached over VGA, turning the LVDS screen off, $ xrandr --output VGA1 --auto --output LVDS1 --off shutting it down and starting it without or with the screen attached, the backlight of the LVDS screen is dimmed. The original brightness (before turning the display off) can be achieved by using for example the hardware buttons. Debian Sid/unstable with Linux 3.19.0 from Debian experimental are used.
Please add drm.debug=14 module parameter and provide dmesg (not journal or syslog) from boot to reproducing the problem.
I think what you will find is the brightness is being preserved by the boot scripts. Only it is restoring the value saved when the screen was off (which is 0).
This bug has been in NEEDINFO state for three months. Please reopen if you are able to provide the requested information.
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