[drm] 3.18 regression: backlight dark after resume

[Ortwin GlÃck]

Hi,

Since 3.18-rc1 backlight is dark after resume from suspend. This is on a Samsung 
laptop with i5 IvyBridge

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor 
Graphics Controller (rev 09)


I have bisected this problem to the following commit:
73580fb764c4213d305c0d36bd8f856ae631eb42 is the first bad commit
commit 73580fb764c4213d305c0d36bd8f856ae631eb42
Author: Jani Nikula <jani.nikula@xxxxxxxxx>
Date:   Tue Aug 12 17:11:41 2014 +0300

    drm/i915/dp: make backlight bl_power control power sequencer backlight

    This lets the userspace switch off the backlight using the backlight
    class sysfs bl_power file. The switch is done using the power sequencer;
    the backlight PWM, and everything else, remains enabled. The display
    backlight won't draw power, but for maximum power savings the encoder
    needs to be switched off.

    Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
    Reviewed_by: Clinton Taylor <Clinton.A.Taylor@xxxxxxxxx>
    Tested_by: Clinton Taylor <Clinton.A.Taylor@xxxxxxxxx>
    Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>


Thanks,

Ortwin
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/