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About a year ago I purchased a fancy new core i7 SSD laptop with nvidia optimus geforce 660M. It's still dual booting windows 7 and ubuntu flawlessly.

There's one major problem though - the lack of ports for connecting external displays, the laptop having only VGA and HDMI. Since I'm often sitting long hours in front of the laptop, using the rather poor build-in display hurts my neck, back and shoulders. So I'm looking for options for expanding my screen real estate using external monitors.

Had I been using only windows I would simply have purchased a USB3-DVI-D converter and connected to one or two 2556x1440 displays - however since linux does not support this display link chip, this is not an option. It's a no-brand laptop, so there's also no official dock available.

Ideally I would like to connect either a 2556x1440 display, but two 1920x1200 displays on a VESA mount is also a possibility (even though that's way more expensive in terms of hardware).

This leaves the following options:

1) Using the good-ol' VGA: The main problem with this is the image quality, I've tried a variety of cables, but the image is always very fuzzy. Also limited to 1920x1200. Is there a way to preserve the image quality of VGA as much as possible?

2) Using HDMI to connect to a 2556x1440 display with a lower refresh rate: After some digging online, I found a few mentions of people driving 2556x1440 monitors using an HDMI port and a high-speed HDMI cable, by creating a custom resolution with lower refresh rate: http://forums.whirlpool.net.au/archive/2037954 http://forum.notebookreview.com/accessories/734218-solved-outputting-2560x1440-1440p-signal-via-hdmi-output.html Does the DELL U2713H support 2560 x 1440 over HDMI @ 60fps Since this is based on a possibly buggy manual configuration I'm a bit skeptical. How important is the refresh rate, is 30hz or 50hz tolerable? I'm not doing any gaming, mainly just looking at browsers and terminals.

3) Use a display-link usb adapter: Apparently, the new version of Ubuntu has built-in support the low-resolution display link chips, although I haven't seen any people actually reporting it working. I'm a bit worried about the quality of the display - is there a degradation of the quality to allow transfer across USB 2?

Maybe I have missed some other options?

I was hoping the smart people here would have some useful insight on what option is best!

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1 Answers1

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I was a bit disappointed about the lack of response to this question, so I ended up taken matters into my own hands and went ahead and tested it myself.

Currently, I can drive a Dell Ultrasharp 27 u2713hm at 40hz with reduced blanking using the hdmi port on my laptop with a 4k hdmi cable in both Windows 7 and Ubuntu 14.04.

To do this in Windows 7, I went into the advanced Intel Graphics settings and created a custom resolution with the above settings. Then I applied the resolution from the main display pane. Going higher than 40hz didn't work. The lower refresh rate is slightly noticeable, but after a while I don't notice this anymore. This resolution setting is correctly recalled after booting.

To do this in Ubuntu 14.04 I had to use Powerstrip in Windows first to generate the command line, and then used:

xrandr --newmode "2560x1440PS" 160,003 2560 2608 2640 2720 1440 1443 1448 1467 -hsync -vsync
xrandr --addmode HDMI1 "2560x1440PS"

To actually active the resolution I had to go into Display settings and manually select the newly appeared resolution. I have not found a way to make this resolution permanent, so I have to redo the entire process at every boot.

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