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From: Arnd Hannemann <arnd@arndnet.de>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: 3.18.0-rc3: i915: eDP connected Display stays blank
Date: Thu, 06 Nov 2014 11:28:52 +0100	[thread overview]
Message-ID: <545B4D64.1010807@arndnet.de> (raw)
In-Reply-To: <87sihw3by4.fsf@intel.com>

Hi,

thanks for your quick response.

Am 06.11.2014 um 10:39 schrieb Jani Nikula:
> On Thu, 06 Nov 2014, Arnd Hannemann <arnd@arndnet.de> wrote:
>> Hi,
>>
>> I have a Thinkpad T440s (Haswell) connected to two additional Monitors
>> via a Docking Station (MST).
>>
>> During Bootup all three displays work, even when X is started.
>> However, if the laptop display is turned off once (either because of
>> power saving, or via xrandr), it fails to "come back".
>> That is if I try to re-enable it the Display stays blank.
>> I believe this used to work in 3.17.
>>
>> Here is the xrandr Ouput of the edp, when its enabled (but staying blank):
>> Screen 0: minimum 8 x 8, current 3840 x 1200, maximum 32767 x 32767
>> eDP1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 175mm
>>    1920x1080      60.0*+   59.9
>>
>> here is the debug output, while trying to enable it:
>>
> 
> ...
> 
>> [  416.538848] [drm:intel_edp_backlight_power] panel power control backlight disable
>>
>>
>> I'm happy to provide further input.
> 
> What does cat /sys/class/backlight/intel_backlight/bl_power say? What if

root@kallisto:~# cat /sys/class/backlight/intel_backlight/bl_power
1

> you echo 0 there?

:-) Works my display comes back, when I echo 0 there.

Is user-space doing something wrong here?

Best regards
Arnd

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  reply	other threads:[~2014-11-06 10:28 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-06  9:14 3.18.0-rc3: i915: eDP connected Display stays blank Arnd Hannemann
2014-11-06  9:39 ` [Intel-gfx] " Jani Nikula
2014-11-06 10:28   ` Arnd Hannemann [this message]
2014-11-06 12:53     ` Jani Nikula
2014-11-07  9:27       ` Arnd Hannemann

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