HDMI issues/not working

i have a Minix Neo Storage Plus and a Hoyoki CB-C71 USB-C hub.

Both work perfectly with my Ubuntu Notebook.

When connected to Librem 5 the Minix shows a waving picture.
With Hoyoki the screen stays black.

I have tired different cables, 2 TV’s, a Dell Monitor.
Always the same, either waving screen(Minix) or black(Hoyoki).

the TV’s and the Dell Monitor are recognized by Settings App. But what ever i tried, resolution, frequencies, etc., nothing worked!

How to get HDMI working?

You can find some information about background and troubleshooting of docked mode here:

If you doubt that your Librem5 is technically o.k. you could try one of the known good adapters you can find here:

merci, will read

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My docking station with external monitor stopped working one day. I went to the cli and did ‘sudo dmesg -w’. I was getting lots of lines to do with the power supply. Turns out I wasn’t using a pd power supply and whatever supply I was using didn’t have the required power to run the docking station. Went back to the charger that came with the phone and it all started working again.

The same with the original power supply. Tried a total of 3 power supplies.

the only relevant dmesg i found is:
[Mo Apr 3 18:21:22 2023] tps6598x 0-003f: The interrupt is masked , how did it fire ?? 380100a

still have to read the stuff from ChriChri!

That’s the TI USB-C port controller. So could be relevant to using a dock or USB-C to HDMI display adapter, and the like.

That error looks a bit suss. If it’s reproducible, maybe report to Purism.


i purchased the USB-C Nano Dock Station (C31NANODOCKLANPD) having HDMI with the least “issues”.

Now i have a picture but no sound over HDMI!
There is no corresponding option in Setttings/Sound. Only build-in.

Is it specific to this USB-C hub or is this feature “HDMI sound” not yet implemented?

Do you selected manually the hdmi output?

Or, precursor question, does HDMI even show up as an available audio sink?

Is this the one that Purism sells? (If so, dare I ask whether you are plugging it in correctly i.e. tail of the hub goes into the Librem 5 and the other USB-C port, at right angles to the tail, is used for power input to the hub?)

Random comment: Another option for debugging video output is to get a USB-C to HDMI adapter.

To be honest, I just went out and bought such an adapter, without any information on this forum or the Wiki as to whether it would be compatible with the Librem 5 - in fact purchased before I even had delivery of my Librem 5. I have tried that adapter on my Librem 5 with two different monitors and it worked with both.

I understand that that is not at all useful if you need the full functionality of a dock - but it can fault isolate.

(I actually don’t need the full functionality of a dock because I am using a Bluetooth keyboard with built-in trackpad. It all depends on your personal requirements, available hardware and setup.)

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As far as I know @dos is working on implementing that. It is not ready, yet, and sound is not working over hdmi, yet.

Any info on when to expect?
i guess it’s a PureOS thing. Couldn’t find any recent Release Calendar with bugs fixed and new features.

Sound over HDMI is already working with the latest kernel, but a) you need to switch to and out of it manually b) the audio device is not clearly labeled in settings. Both of those things will be fixed by librem5-base update that’s about to migrate over the next week. You will still have to switch the audio device manually the first time, since there’s no way to detect whether the connected screen actually has any means to output the audio (some screens only have a headphone jack, for example), but once you do that it will properly switch on hot plug and unplug.


What about audio through the usbc port connected to a nexdock for example?

What about it? If it’s a USB audio device, it’s completely unrelated to HDMI/DP.

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Sorry I’ll start a new thread.