USB-C device fails to enumerate when connected directly (possible Alt Mode / role negotiation issue)

Help Fairphone 5
1

Hi,

I’m experiencing an issue with a USB-C accessory that connects directly to the Fairphone 5 via the USB-C port.

The device works correctly on other Android phones (including older USB-C 2.0 devices without DisplayPort Alt Mode), but on the Fairphone 5 it fails to initialize properly.

Observed behaviour:

  • The device does not enumerate as a USB HID.

  • Attempting to switch “USB controlled by” to “This device” results in either:

    • “Couldn’t switch”

    • Or a “Debris or liquid detected in USB port” warning.

  • The USB-C port is clean and functional (external display via DP Alt Mode works fine).

  • The accessory works immediately on another phone (Pocophone F1).

This suggests a potential issue with:

  • USB-C role switching

  • Power Delivery negotiation

  • Or DisplayPort Alt Mode interfering with USB enumeration

The device appears to expect standard USB 2.0 host behaviour, and may not handle DP-Alt negotiation correctly.

Questions:

  1. Is there a way to force USB 2.0 host mode (disable Alt Mode negotiation)?

  2. Has anyone observed USB-C composite devices failing to enumerate?

  3. Is this something that could be improved in firmware?

Thanks in advance.

2

Hello !

I’m experiencing the same problem with an FP5 and a UGreen 5-in-1 USB-C hub.

When I plug in the HDMI cable, Android asks me if I want to duplicate my display, but no matter what I say, nothing appears on the secondary screen.

I hope an update will fix this… it would save me from having to buy a laptop just to project a few slides in class…

Thanks in advance!

3

Same issue here.

I am plugging a baseus metal gleam series 9 in 1 port connected via hdmi to a monitor into my fair phone 5. My charger is also plugged into the baseus port. When connecting the baseus port to the fair phone 5 the option to mirror to external display pops up and the monitor exits sleep mode but the monitor only says no signal. On my fair phone 5 I have developer options toggled on, USB debugging is on and the default USB configuration is set to MIDI. I have tried plugging the baseus port in while my phone is on sleep mode. I have tried rotating the baseus usbc cable 180 degrees but nothing seems to work. The baseus website says the port requires a phone/laptop with DisplayPort Alt Mode (DP Alt Mode) which I am pretty sure the fair phone 5 has. The baseus port works fine for my laptop so the baseus port is not broken.

4

Indeed, I reckon these issue started in Android 15 and never got addressed.

5

I saw a video of a guy running linux on his fairphone 5 and he was able to use a different baseus dock. But I also read that some docks “just work” with fair phone 5 and others dont.

6

Try to connect a power supply to the doc before connecting the HDMI.

7

Unfortunately, it doesn’t work. I tried it with my partner’s FP4, and everything works perfectly. I conclude that my U-Green hub 5 in 1 doesn’t seem to be the problem. :frowning:
I sincerely hope the Fairphone development team releases an update for FP5 and Android 15 or update to Android 16 so that restores this feature, which is—in a way—eco-friendly (it could save me from having to buy a laptop!!).

8

I have a “mobility lab” USB-C hub and it works with my Fairphone 5 on Android 15 with a LG 2016 OLED TV.

If you can try another hub, test, it may be an USB-C problem on your Fairphone if none works.