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I'm trying to use xrandr to add a custom resolution for my 2560x1080 AOC monitor.

I've been given the VESA timings by the manufacturer (attached), but I'm not sure what I should be doing with them:

VESA Timings

I'm using cvt to generate a ModeLine (cvt 2560 1080 60.00), which generates:

# 2560x1080 59.98 Hz (CVT) hsync: 67.17 kHz; pclk: 230.00 MHz
#Modeline "2560x1080_60.00" 230.00 2560 2720 2992 3424 1080 1083 1093 1120 -hsync +vsync

I can use xrandr to add that Modeline, then add it to HDMI1 - but when I set the monitor to the new resolution, all I'm getting from the monitor is flashing colours, until I drop it back to 1920x1080@60.00.

The laptop I'm using is an Acer Aspire v7-581PG - which has a 720M chip, so using Optimus (I also have bumblebee installed), but it seems that anything being output over HDMI uses the Intel chip anyway (which I believe is a 4400 chipset from the i5)

If I go into nvidia-settings with:

# optirun nvidia-settings -c :8, 

I get to the settings menu, but no monitors are displayed there - so I assume everything's being handled by the Intel chip?).

I know the chipset CAN handle HDMI @ 2560x1080, as Windows 8 had no troubles outputting properly.

I assume I'm doing something wrong with the timings here, but I just can't work out what. I've tried dropping the refresh rate down in decrements of 1, all the way down to 40, but I get the same result - once I get down to 47.00, it just shows a black screen, rather than flashing colours.

Any help would be hugely appreciated. Having a 21:9 monitor running at 1920x1080 is annoying enough to make me consider switching back to windows!

Just to follow up, looking at the VESA timings, the nominal frequency is 181.250, so I have tried the following but get the same issue:

#Modeline "2560x1080_60.00" 230.00 2560 2720 2992 3424 1080 1083 1093 1120 -hsync +vsync
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Just to follow up, looking at the VESA timings, the nominal frequency is 181.250, so I have tried #Modeline "2560x1080_60.00" 230.00 2560 2720 2992 3424 1080 1083 1093 1120 -hsync +vsync but get the same issue –  user200427 Oct 10 '13 at 8:57
    
I have same problem with lg-25UM65-P (21:9 inches). it works great on windows 8.1 and has output of 2560 * 1080 automatically over HDMI (which some think that's the problem which is not!). but i searched a lot and got nothing about Ubuntu and my nvidia GEFORCE 610M-2GB. –  hosein kazemi Jul 7 at 7:16

1 Answer 1

I have connected ultrawide monitor by HDMI with

Modeline "2560x1080_40.00"  147.25  2560 2680 2944 3328  1080 1083 1093 1108 -hsync +vsync

I used:

cvt 2560 1080 40

HDMI did not support > 165 Mhz, however HDMI 1.3 supports up to 340 MHz maximum pixel clock rate wiki.

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