For my use case I'm trying to take a clean install of Ubuntu Core on a Raspberry Pi 5 and run the suggested demo of Ubuntu-Frame. However, the Ubuntu-Frame demo fails to work.
My steps start with a clean install of Ubuntu Core run `sudo snap refresh` modify the /run/mnt/ubuntu-seed/config.txt to use vc4-kms-v3d run snap install ubuntu-frame wpe-webkit-mir-kiosk run sudo snap set wpe-webkit-mir-kiosk url=https://ubuntu.com/core I can confirm this issue affects Raspberry Pi 5 Model B Rev 1.1 (not just Compute Module 5) running Ubuntu Core 24 with identical symptoms. Hardware & Software - Raspberry Pi 5 Model B Rev 1.1 - Ubuntu Core 24 - pi-kernel: 6.8.0-1039.43 (24/stable) - SAME kernel version as original report - pi gadget snap: 24-3, Rev 151 (24/stable) - ubuntu-frame: 393-mir2.23.0, Rev 17237 (24/stable) - Firmware: 2025-03-10T17:10:37 Symptoms 1. vc4 kernel module loads but has 0 usage count (never binds to hardware) 2. Device tree nodes for HDMI, HVS, and pixelvalves exist BUT all have status="disabled" 3. No platform devices created (only axi:gpu exists) 4. /dev/dri/card0 never gets created 5. ubuntu-frame fails with "No DRM devices detected" 6. dmesg shows ZERO vc4 initialization messages Critical Finding - Both Overlays Fail I tested BOTH device tree overlays with identical results: - `dtoverlay=vc4-kms-v3d,cma-128` → device tree nodes disabled, no /dev/dri - `dtoverlay=vc4-kms-v3d-pi5,cma-128` → device tree nodes disabled, no /dev/dri The Pi 5-specific overlay makes NO DIFFERENCE. Both overlays result in: ``` $ cat /sys/firmware/devicetree/base/soc/hdmi@7ef00700/status disabled $ cat /sys/firmware/devicetree/base/hvs@107c580000/status disabled $ ls /dev/dri/ ls: cannot access '/dev/dri/': No such file or directory ``` This suggests the problem is NOT the overlay choice, but rather 1. Both overlay files (.dtbo) in the pi-kernel snap are broken/incomplete for Pi 5 2. The bootloader/firmware isn't properly applying overlays on Ubuntu Core 3. Something in Ubuntu Core's boot process is disabling device tree nodes after overlay loading 4. The initrd or pi-gadget snap is interfering with device tree initialization Device Tree Evidence ``` $ cat /sys/firmware/devicetree/base/axi/gpu/compatible brcm,bcm2712d0-vc6 $ lsmod | grep vc4 vc4 479232 0 $ sudo dmesg | grep -i vc4 [empty - driver never attempts initialization] ``` The vc4 driver's component framework waits for all display components (HDMI, HVS, pixelvalves) to be enabled before binding. Since they remain disabled regardless of overlay choice, the driver never initializes. Questions 1. Are the vc4-kms-v3d-pi5.dtbo and vc4-kms-v3d.dtbo files in pi-kernel 6.8.0-1039.43 known to create disabled device tree nodes on Pi 5? 2. Does Ubuntu Core's bootloader or initrd handle device tree overlays differently than regular Ubuntu? 3. One user successfully deployed ubuntu-frame on Ubuntu Core 24 + Pi 5 (without proof)[Ubuntu Discourse, Aug 29 2025](https://discourse.ubuntu.com/t/how-to-rotate-touch-screen-input-on-ubuntu-frame/66283) - what configuration made it work? This appears to be a fundamental incompatibility between Ubuntu Core 24's pi-kernel snap and Raspberry Pi 5 hardware that affects ALL device tree overlay configurations. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2128161 Title: pi-kernel VC4-KMS not working with CM5 To manage notifications about this bug go to: https://bugs.launchpad.net/canonical-kernel-snaps/+bug/2128161/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
