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I have the motherboard "Gigabyte Z77x-ud3h" with a 3rd Gen Intel CPU with HD4000 graphics. I am using Ubuntu 12.10.

When I connect one monitor (Dell 3011) with DisplayPort and a second monitor (Iyama) with HDMI, after a while the Dell goes into power saving mode.

When I connect just the Dell monitor (DisplayPort), it works, and also when Dell is connected by DVI, but then I don't get full resolution.

Why does the HDMI monitor go to sleep after a while when another monitor is simultaneously connected with DisplayPort?

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How long is "a while"? Is this after 10 minutes of activity, or while you are using it? Are you able to wake it up when it goes to sleep? If it just goes to sleep while you are actively using the computer, it is likely a bug. You can file it in Ubuntu, but it is more likely to be seen if you file it upstream as well and link to the Ubuntu bug. You might also test with the xorg-edgers PPA first to see if the bug is already resolved in the development version of the graphics stack. –  ÃŁŁǫǛȉЖΦΤїҪ Oct 30 '12 at 21:32
    
while - about a minute. it can wake up by let's say changing screen resolution. –  greg606 Oct 30 '12 at 23:14
    
I believe this is a bug in 12.10. I observe exactly the same thing after upgrading from 12.04. Also Intel HD4000 graphics, also a Dell 3011 over Display Port and secondary monitor (though my secondary monitor is DVI). This happens after whatever the inactivity/lock time seems to be. I thought changing "Dim screen to save power" or "turn off screen when inactive for" in "Brightness and Lock" settings might help, but this doesn't seem to have an effect. I couldn't find an appropriate bug in launchpad, nor do I know which package it should be filed against. If you file one, I'd be happy to click –  user169159 Oct 31 '12 at 14:20
    
@allquixotic said: "You might also test with the xorg-edgers PPA first to see if the bug is already resolved in the development version of the graphics stack." I think that was a great suggestion. I've just tried it though, and it doesn't solve the problem. –  user169434 Nov 1 '12 at 15:30
    
Another similar situation: I have a Dell M4700 + Quadro K4000M + Windows 7 + 2x Dell U2913WM monitors + Wacom Cintiq. When the U2913WM's are connected using DP1.2 MST daisychaining, one of them will eventually enter "Power Save Mode" unexpectedly. I've got a support case open with Dell, but no solution yet. –  alx9r Aug 2 '13 at 20:58
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1 Answer

I have a ThinkPad 420 (Intel HD Graphics) connected to a Dell 3011 monitor through DisplayPort, and I started having the same problem after upgrading from Ubuntu 12.04 to 12.10. I get about a minute of usage before the monitor goes blank, unplugging the DisplayPort and plugging it back in gives me another minute of picture. With 12.04 I had no problems, and used it with this monitor for about a month.

The only "fix" I've found so far is to boot into one of my old Ubuntu 12.04 kernels (I'm typing this on 3.2.0-32). This improves the situation a bit, but the monitor still periodically goes into power save mode (sometimes after 30 minutes, sometimes I get a few hours). 3.2.0-32 seems to work just fine with the 12.10 user space.

To boot into an old kernel, just hold down the shift key while the system is booting (while your BIOS screen clears) and choose Advanced from the GRUB menu. Unless you uninstalled your old kernels after you upgraded, you'll probably have a few 3.2.0 kernels still in the list.

If you didn't upgrade to 12.10 (fresh install), I don't know an easy way to install kernels from an older distribution, but there's probably a trick to do it with apt.

I'd file a bug if I had any idea what to file it against. I originally suspected this was an X issue, but the old kernel certainly changes the behavior, and I had no problems with 12.04. May it's a DRM thing, or a DRM + X thing?

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Here's a weird data point: if I boot 3.5.0-21 (the one that was causing the most problems), and wait until the problem happens, then run "xrandr --output DP1 --set audio off" to disable the audio device built into the monitor, the picture comes back! After turning it off, I get a few weird flashes across the display every few minutes, but it doesn't dive into power save mode. Hoping this keeps working, I'll report back if it doesn't. –  Shaw Terwilliger Dec 23 '12 at 18:47
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