Ultrawide monitors - Hardware talk
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Hey Nixers,

Managed to get an ultrawide monitor for xmas (21:9 2560x1080 LG 29UM67 29") and spent some good time fiddling with Xorg.conf.

I thought those days were over...

After messing around with modelines and an abundance of settings in Xorg.conf, I managed to get my native resolution working... at 30Hz. It's not the best experience, but its better than the highest default supported Xrandr mode of 1920x1080 at 60Hz. For the record I am running xf86-video-ati on Crux 3.2.

The problem is that if I try to run my native res (2560x1080) at 60Hz (also tested at 55Hz), my monitor is not able to display the desktop correctly; there are several artifacts and the framebuffer is completely jagged.

I'm curious to know if anyone else has any advice or info on getting ultrawides to work. I've been doing a lot of google searching to see if there is anyone else who has a problem similar to mine. It seems like they did, initially. Xrandr wasnt detecting their native resolution and all they had to do was set a modeline.

Thanks guys, hope you're all doing well.

A quick update, I managed to get up to 40Hz on my native resolution of 2560x1080. For reference, here are the working modelines, respectively:

2560x1080 @ 30Hz
Code:
Modeline "2560x1080_30.00"  106.75  2560 2640 2896 3232  1080 1083 1093 1102 -hsync +vsync

2560x1080 @ 40Hz
Code:
Modeline "2560x1080_40.00"  147.10  2560 2680 2944 3328  1080 1081 1084 1105 -HSync +Vsync
venam
Thanks for the info.
Threads like that are nice as reference for others.
If I get a wide monitor, which I would like to get, this would be super helpful.
Sorry I ain't got no clue on how to fix the issue with the refresh rate.
apk
No problem venam, I'm glad to hear I can be of assistance.

To add some more info, I do have a specific usecase. I'm not sure if the kernel, graphics driver, Xorg itself, or the video cable I'm using (HDMI) is preventing me from having a useable refresh rate. I'll attempt to see if catalyst (proprietary ati driver) does anything better.

In general, if Xorg doesn't automatically detect the native res and refresh rate, what you will be doing is generating a modeline using either
Code:
cvt
or
Code:
gtf
. For example, to get my 2560x1080 @ 40Hz modeline:
Code:
$ gtf 2560 1080 40
then copy that into /etc/X11/xorg.conf or /usr/share/X11/xorg.conf.d depending on what distro you use. THEN, restart X and hope the goat you sacrificed pleased the Xorg gods.
xero
>modeline

motherofgod.jpg
vain
Oh dear. :-)

For what it's worth, I came across some of these monitors (a different vendor, though) and they claim their native resolution only works over DisplayPort, not HDMI. Maybe that's an option for you.
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(28-12-2015, 08:07 PM)vain Wrote: For what it's worth, I came across some of these monitors (a different vendor, though) and they claim their native resolution only works over DisplayPort, not HDMI. Maybe that's an option for you.
I fear that my hardware choice may be what is preventing me from running at 60Hz. I was also considering trying a dual link DVI cable as the monitor itself stated to use that. However me and my ignorance believed I had everything under control... once again that was proven wrong :). If hardware is the case, I may be in the market for a new GPU then... good thing I'm getting paid in a week.
(28-12-2015, 04:22 PM)xero Wrote: >modeline

motherofgod.jpg
All part of the experience my good sir :)
Wildefyr
AMD drivers are probably the issue. If you are in the market for a new GPU just save yourself the hassle and buy a nvidia card.
apk
Using an nVidia card (GTX 550 Ti) with both the binary blob and nouveau worked. Surprised that the open source ati driver did not. I have a new card (HD 7770) coming in next week that I'll try as well.


I'm getting too carried away with this.




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