USB-C display n00b question

[Niftyprose]

Hello guys, I suspect that this is one of those queries the answer to which is really obvious after the fact. Sorry if anyone's groaning inwardly. Context:

I recently bought a mini-PC with lots of ports. One of them is a USB-C port with display functionality, my first encounter with this technology. I also bought a portable monitor with a single USB-C port. The makers of both these devices encourage new owners to connect their products via a single USB-C to USB-C cable which carries both signal and power, making for a logical and robust setup.

The mini-PC arrived with a full Windows installation, and this setup worked perfectly out of the box. However, when I tried to load Q4os Linux, I encountered display problems. The mini-PC still powered the monitor, but it offered only 800*600px resolution, a setting which is inappropriate for a modern 16:9 monitor. I'm used to occasional display problems with the Trinity display environment so I tried a succession of other Linux distros. All of them were stuck on 800*600. It was only when I eventually installed Linux Mint Cinnamon that I got access to higher resolutions.

Linux Mint has worked out very well on this particular computer, and I've since learned that Ubuntu would also have worked -- so, no technical fix needed. Instead, my query is long-term and background-related. I can't see anything in the Mint or Ubuntu documentation that says "supports USB-C display at all resolutions". How can I tell which Linuxes are likely to support USB-C display without going to the trouble of installing them?

 

[CaffeineAddict]

Here is something worth reading:

ThinkPad Universal USB-C Dock: Somehow recognized, but monitors, ethernet and fwupd don't work with T570

I have a "ThinkPad Universal USB-C Dock" (Link to German Lenovo page) that works reasonably well with a DELL 5560: Monitors via Displayport, Ethernet, USB, fwupd all work. The DELL is run...

unix.stackexchange.com

 

[Niftyprose]

I ploughed dutifully through the article but without much illumination, I'm afraid. If I've understood it correctly, Linux connectivity problems including those affecting USB-C displays can arise:
*from failure to configure Thunderbolt componentry
*from failure to install an updated kernel
Since there's no Thunderbolt componentry in my setup, the import of the article amounts to: "does your Linux kernel support a full range of resolutions via USB-C?" which sounds much like my initial query, rendered slightly more specific.
So, can anyone tell me when the Linux kernel was tweaked to support resolutions higher than 800x600 via USB-C?

 

[bob466]

I once ordered a pack of Flash Drives from Amazon...when I got them they were USB-C...which were no good for me as all my computer ports are USB-A...back they went...stupid me.

 

[Trml]

I don't know either Mint of Q4OS, but a distinction may be Mint may already use wayland and Q4OS X11.

This is relevant because X11 may fallback to helper modules (800x600 resolution is a safe mode), if you don't configure the display explicitly in configuration while wayland is autoconfiguring displays.

 

[Niftyprose]

Hi Trml, thanks for your response.
In answer to your implied queries:
Q4os is a Debian branch Linux which originally used the Trinity desktop environment, a solid but little-used KDE fork. (The only other Trinity-based distro I know is the obscure EXE Linux.) Q4os now offers a Plasma variant, but I've stuck with the original.
Mint is also Debian branch and multi-flavour. The variety I downloaded for this exercise uses the Cinnamon environment, created in-house by the Mint team and apparently derived from XORG, with Wayland support currently being added piecemeal. It's impossible to tell whether it was the XORG or the Wayland aspects of Cinnamon which made it work in my particular case.
FYI, I installed five different Linuxes and none of them offered any display configuration options during the install process. In #s1--4, the "X11 fallback" limiting the display to 800*600 appeared to trigger automatically as soon as the installer(s) detected USB-C hardware. I tried #5, Mint, on a hunch.
I posted this query to learn how to identify whether or not a particular Linux is likely to provide a full range of resolutions on a USB-C display without having to rely on hunches. Sadly, I don't think "Has it got Wayland?" will yield a definitive answer. What will?

 

[Trml]

It's impossible to tell whether it was the XORG or the Wayland aspects of Cinnamon which made it work in my particular case.

You can rule out it was wayland simply by looking if it is in use. I would not call that an impossible mission. Wayland support is added piecemeal to applications, which use xwayland while the transition is in progress. With xorg you have to configure the display resolution you intend to use. Have a search for that with the distro you want to use, you unlikely will be the only user with usb-c display.

 

[Niftyprose]

Well, that's good general-purpose advice, f'sure, Trml. But I have this lingering sense of frustration (not with you!) If I were choosing Linuxes the way I choose breakfast cereal, I'd expect to find accounts of graphics capabilities to be printed on the outside of the packaging, if you take my meaning? I know our favourite OS family is mostly free, but, still...

 

[Trml]

Don't bring cereal into the equation, there is a lot of grief with package information on cereal boxes. First, manufacturers have to be forced to print basic nutrition data onto it, second they haggle down the standards for years until it ends with a printed label that helps them but noone who truly has specific dietary requirements (does a statement like "may contain nuts" help with a hazlenut allergy?). Sending a fussy shopper, who may require bio or fair trade products, brings another set of labels - each requiring a detail level research if it is a marketing gimmick, or testament of a defined and controlled produce quality. Buying cereal is definitely more complicated than plugging in a hdmi cable into a cereal-box PC and doing the research of the topic at hand with high resolution.

But, don't take offense, just my personal take on it. Let's wait if someone has an idea what ingredient may be missing.

 

[Niftyprose]

Heh. You may be right. I'm reminded of the (apocryphal) tale of the nutritionist who found you'd be better off eating the cardboard packaging than its contents...