Linux Multi-Monitor Support Could Be Improved

[schmidtbag]

That's not an option for me because my second monitor is a Wacom Cintiq 12WX (1280x800) while my main monitor is 1920x1080. So for me it's annoying since I need my Wacom to be hooked up and working most of the time (without having to adjust settings in the AMD Catalyst Control Center), but I also want to play games sometimes. I've gotten most games to run, but usually there's problems (maybe Gnome-Shell specific) and the resolutions are sometimes limited to the Cintuq's aspect ratio.

Well, considering you don't hold the tablet up to be in your view while gaming, I feel like there are ways to avoid using it for games. For example, does it make a difference if you virtually stack the displays vertically instead of horizontally? Also, you could try doing a multiseat situation which I think would actually be more ideal for whatever you do on your tablet - the tablet can be used strictly to draw/edit while you have a separate mouse and keyboard for nagivating your main screen. To me, that's something to really show-off to Windows users. If you need to type, put on an on-screen keyboard. Anyways as a last method, you could also try just simply disabling the screen when playing games but I'm pretty sure you'd have thought of that already.

[F i L]

Well, considering you don't hold the tablet up to be in your view while gaming, I feel like there are ways to avoid using it for games. For example, does it make a difference if you virtually stack the displays vertically instead of horizontally? Also, you could try doing a multiseat situation which I think would actually be more ideal for whatever you do on your tablet - the tablet can be used strictly to draw/edit while you have a separate mouse and keyboard for nagivating your main screen. To me, that's something to really show-off to Windows users. If you need to type, put on an on-screen keyboard. Anyways as a last method, you could also try just simply disabling the screen when playing games but I'm pretty sure you'd have thought of that already.

I do use vertical monitor setups. The pictures below are of my computer setup. They're about 9 months old (and that's why you see Windows running), but my setup is still like that (now dual booted with Arch and Win8):

Pictures:
Picture 1
Picture 2


The problem I have with a multi-seat system is:

a) having to figure out how to do that

b) Gnome-Shell difficulties or general desktop panel clutter and multiple input (often I want a keyboard for the second monitor)

c) Most of the time I don't play games on Linux. I play CS:GO and Skyrim on my Windows boot, but I can't play those on Linux anyways So I'm more inclined to just keep things setup in a standard, easy-to-use way, and pass on the games that do work properly on Linux (Xonotic, Alien Areana, etc). I'm really hoping that Steam will properly support Linux games multi-head setups.

d) I've gotten those games to run, but there's always some difficulties. There must be a way to make a full-screen application function properly in Linux with a dual-head setup, and so I don't think I should need to change anything on my end, i'll just report issues and hope they get around to supporting my system better.


Thanks for the suggestions, though I am looking into any alternative options.

[Lemonzest]

Yes. But I think the behaviour with fullscreen applications can vary. Usually a fullscreen application will grab the mouse so you can't move the pointer onto another display and have that application lose focus. That's almost always what you want though.

It may depend on which desktop you're using but at least with XFCE, applications will open on the display where the icon was clicked. Otherwise, start the application with DISPLAY=:0.1 or some applications accept a -display argument.

It's also worth remembering multiple pointers too. If a fullscreen application grabs the mouse, you could potentially have another one on another display for doing other things. However, the last time I tried this with XFCE, the first pointer was always grabbed regardless of which one actually clicked the application icon.

Thanks for that, pretty much as I assumed, I'm using GNOME 3.4.4 and with two screens its pretty much built in, tho I had to tell SDL apps to not use xrandr or it fills the second screen when it exits, and some SDL games see it as one surface and strech the whole game across both, no idea what till happen when I add a third in a few weeks time (have the screens, just not a big enough desk for 3x 24" screens!)

[Hamish Wilson]

In Zaphod mode, I know you can't drag windows, but will the mouse Pointer go between monitors? I plan on setting up 3 soon, and wondered if xrandr or Zaphod would be better.

Yes, of course. But it all depends on your use case which is better for you.

Also, keep in mind that some desktops such as Gnome Shell do not work properly with Zaphod Mode. LXDE and Openbox work, but only on one screen. KDE is supposed to work, I know Xfce does, and I have used Blackbox and Zaphod as well.

[schmidtbag]

The problem I have with a multi-seat system is:

a) having to figure out how to do that

b) Gnome-Shell difficulties or general desktop panel clutter and multiple input (often I want a keyboard for the second monitor)

c) Most of the time I don't play games on Linux. I play CS:GO and Skyrim on my Windows boot, but I can't play those on Linux anyways So I'm more inclined to just keep things setup in a standard, easy-to-use way, and pass on the games that do work properly on Linux (Xonotic, Alien Areana, etc). I'm really hoping that Steam will properly support Linux games multi-head setups.

d) I've gotten those games to run, but there's always some difficulties. There must be a way to make a full-screen application function properly in Linux with a dual-head setup, and so I don't think I should need to change anything on my end, i'll just report issues and hope they get around to supporting my system better.


Thanks for the suggestions, though I am looking into any alternative options.

In Windows, there's no way to do multiseat for free. In linux you can follow this guide (which just happens to be Arch based). As another alternative that I personally find easier, you could look into xinput2 commands to spawn additional master input devices (part of MPX) and use your 2nd mouse and keyboard inputs in a xephyr window. It won't be GPU accelerated (unless you use virtualgl) but I've found it to be pretty effective alternative. I unfortunately lost a lot of documentation that I used to set up something like this but the xinput commands to spawn additional masters is pretty easy and seems to be exactly what you're looking for when it comes to multiple keybords.

[korrode]

I must be a rare case in that I have no want or need to drag apps from one screen to another, I run "separate X screens". I kinda just designate different screens for different types of task and run 8 virtual desktops on each. Everything works perfectly for me, full screen gaming included.

[Hamish Wilson]

I must be a rare case in that I have no want or need to drag apps from one screen to another, I run "separate X screens". I kinda just designate different screens for different types of task and run 8 virtual desktops on each. Everything works perfectly for me, full screen gaming included.

Actually, looking at this, you are less of a rare case than some might have thought. A lot of support for Zaphod has appeared on this thread.

[mtk0]

Xinerama doesn't have compositing. Fine, Nvidia's twinview only supports 2 screens but has compositing. So I setup two cards and separate x servers. But kde doesn't work well with multi-head and needs rewritting.

Wasn't there a time when linux was used for bleeding edge hardware and setups, or was it always just to revive old computers?

life with more than 2 screens, nvidia, and KDE is always... difficult. particularly the KDE part. hard to imagine why this is so but it has been and continues to be a big fail. has anyone switched to XFCE w/multiple monitors and been happier?

[M1AU]

I can also confirm this behavior. Had exactly the same problems with multi-monitor setups on Linux for the past 6 years while gaming as described in the article.
Most of the problems could be solved, but only with some hack load of work.

[Ansla]

life with more than 2 screens, nvidia, and KDE is always... difficult. particularly the KDE part. hard to imagine why this is so but it has been and continues to be a big fail. has anyone switched to XFCE w/multiple monitors and been happier?

I'm quite happy how KDE handles multiple monitors with the radeon driver, what exactly are you missing?