It doesn't sound like you have used Linux since 1998. It works "out of the box" with multiple screens no matter the DPI.

Ehh, screen zoom could be better on 4k monitors. I always find the display scaling to be WAY off by default and have to mess around with xrandr settings in the terminal to change fractional scaling. This (and many other basic setup issues) doesn't make for a great first-hand experience when first starting out with Linux.

https://wiki.archlinux.org/index.php/HiDPI#Fractional_Scalin...

I tried an Ubuntu 17.10 live image yesterday on a Thinkpad P50 with a connected Samsung 4K display, and my experience was not as you describe.

I'm not having any problems running two monitors in HiDPI with my Ubuntu Studio workstation .. everything just works and I enjoy it immensely. Curious what your issues are...

To be fair, some applications on some distros have HiDPI issues. LibreOffice [0], icons in GTK2 apps, anything that uses Java Swing, etc. Particularly galling is the oft-suggested fix of temporarily reducing desktop resolution and fowling up all the other apps that are supporting the proper DPI.

[0] https://bugs.documentfoundation.org/showdependencytree.cgi?i...

> anything that uses Java Swing

OpenJDK 9 supports HiDPI out of the box[1].

[1] http://openjdk.java.net/jeps/263

That he hasn't actually tried Linux.

Using Fedora and two HiDPI monitors, one landscape 4k screen and one portrait 2k screen, Gnome works great in this setup.

More common setup of one hidpi screen with another normal dpi screen (laptop + external screen) tends to break horribly in many cases though.

Don’t know about GNOME but recent KDE can handle that case just fine.

Sounds like a pretty edgy edge case to me. In a more typical deployment like a laptop with a built in display or a desktop with a single 1080p or 1440p monitor you can pick from a variety of distributions that on firm "it just works" territory.

I have a nice laptop, with a 3k display. I plug it to a normal screen, with a 1080p display. What happens? Well, it works but it looks like ass. Wanna fix it? Sure, just google around for 2 hours until you find a complicated xrandr command that you have to run every time on startup (but the OS will break every time you unplug the screen). Also, high DPI support is still garbage, which means that half the apps will have their text looking too small anyway.

So no, I don't consider it an "edge case" if everyone in the office with a Linux laptop has the same problem

It still is an edge case when the case is rare and people with high dpi Linux laptops (or monitors in general) combining them with regular dpi monitors is rare. Hell, high dpi monitors by themselves are still rare.

Pretty much any MacBook connected to an external monitor falls in this "edge case". Or any modern MacBook-class laptop. They might not be the majority, but they are still a group of people counted in millions.

It's only an edge case on Linux because anyone trying to use such a laptop on Linux is met with pretty much unacceptable breakage and has to move away to Windows or macOS.

It's as rare as high dpi laptops, which are less and less rare nowadays. If you have a laptop, you're gonna plug it to an external screen at some point, and regular dpi screens are very not rare. This shortcoming is indefensible and should've been fixed years ago

The intersection of people that care about high dpi laptop screens, but not about high dpi external screens is very, very small. Also, if you are in that group, why wouldn't you just turn down the resolution on the laptop or even turn it off (since you connected a low dpi external monitor, you don't seem to care about the additional sharpness of high dpi, right?)?

High dpi is important as is low dpi (for a while still at least), mixed dpi is an edge case even if you disagree.

I'm running linux with a 4k monitor and a 2560x1600 monitor, and it's plenty smooth. It is worth noting that I have a GTX 1080, but everything else in the system is 7 years old.

You don’t need a GTX 1080. Any modern low-end GPU like RX 550, GTX 1030 or the new Ryzen APU would be fine. Even higher-end Intel iGPUs should work[1].

Basically all you need is at least DisplayPort 1.2 (or 1.2a if you want Freesync) for 4K @ 60 Hz.

The RX 550 has 1.3 support, so it should handle up to 2x4K @ 60Hz with MST (daisy-chained or with a splitter) or a single 5K @ 60Hz.

Some 4K monitors can also work with 2×HDMI, but I don’t think you’ll find that on any low-end card. Maybe high-end used.

As for actual performance, there is a huge gap between what you need for gaming and what you need for office work.

A low-level graphics card from few generations ago with 1GB of VRAM would be fine even (like Quadro 2000), except that it will only be able to drive the display at 30 Hz.

The biggest gotcha with a 4K display is actually your host RAM. If you try to run anything like GIMP, Photoshop, or vector editors in particular, it will gobble up much more memory than usual. Your regular web browser will as well, though to a much lesser degree.

Getting something just a little better, like an RX 560, might be a good idea though, this gives you enough GPGPU power to run most expensive video filters and scalers at native 4K[2].

[1] My Apollo Lake netbook with an entry-level iGPU can handle a 3K display easy

[2] Your source material might be 1080p but you end up postprocessing it at 4K. This might surprise some people.

To some, that is good. Despite fancy displays, the terminal is still far more efficient in my opinion for many operations, although graphics are nice for things and those things work great on Linux