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#1 2012-08-21 12:26:43

btorb
Member
Registered: 2012-08-06
Posts: 28

*DON'T* blank screen when closing the lid

My computer suffers from occasional crashes after resuming from suspend or hibernate. As a final attempt to resolve it (unfruitful attempts are widely documented, for instance here), a friend suggested that the problem might be caused by the intel driver (i have a lenovo t420s with intel graphics) having to deal with "succesive" power-offs:

1. pm-suspend (amongst others) switches off the screen and waking up also brings back the screen.
2. *somewhere/somehow* closing the lid also causes the screen to blank

Now I have uninstalled acpid and no events (such as closing/opening the lid) are managed anymore. Moreover, in /proc/acpi/wakeup, i disabled to wake up from lid option.

Strangely enough, the screen is still blank when i close the window (try it yourself, slowly close the lid and when it's nearly closed, the screen blanks). So, i looked at display power management wiki from arch and did what they said. No result, the screen still blanked when closing the lid. So it appears to be a very low level setting. In my computer's BIOS I couldn't find anything that relates to blanking the screen. So it must be software regulated.

Anyone knows how to avoid blanking/witching off the screen when closing the lid. I don't want any lid event to interfere with the pm-utils and avoid the "double" blanking/sleeping/swithing off/awakening of the screen. Many thanks!

EDIT:
I run openbox as WM and have now gnome or any DE installed. (My friends idea is also inspired by the warning given on the acpid wiki, that different "power managers" can interfere with each other)

Last edited by btorb (2012-08-21 12:30:15)

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#2 2012-08-21 12:48:58

Trilby
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From: Massachusetts, USA
Registered: 2011-11-29
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Re: *DON'T* blank screen when closing the lid

On some laptops this is not software nor bios, it is a purely hardware switch: when the screen reaches a certain angle the power to the screen is shut off.

Does this lid-closing cause problems similar to acpi-driven screen shut off?  If it is purely hardware it shouldn't.  AFAIK (which may not be very far) such hardware switches do not interact with the video card or any other components - it's purely a power cut-off to the monitor.


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#3 2012-08-21 14:25:23

btorb
Member
Registered: 2012-08-06
Posts: 28

Re: *DON'T* blank screen when closing the lid

Trilby wrote:

Does this lid-closing cause problems similar to acpi-driven screen shut off?  If it is purely hardware it shouldn't.

I don't think it is purely hardware as it sometimes causes the screen to go to the state in which one third remains black and one third is scrambled. (This is some issues with the driver and is also widely described, for instance here

Last edited by btorb (2012-08-21 14:26:35)

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