After the release of Ubuntu core 18 for raspberry PI 4 I decided to test the chromium-mir-kiosk, which unfortunately does not start, logs below.
snap logs mir-kiosk:http://dpaste.com/3CJMWJG
snap logs chromium-mir-kiosk:http://dpaste.com/08T99R4
Hi @malt, thanks for the feedback.
Two things:
- chromium-mir-kiosk is unsupported, and we recommend wpe-webkit-mir-kiosk as a possible replacement.
- I’ve not got a RPi4 to test with, but on checking with someone that has, it seems there are problems with some “kiosk” snaps. Particularly those that, like chromium-mir-kiosk, use Xwayland.
I should have access to a RPi4 next week to investigate further. Thanks again for bringing this to my attention.
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Hi @alan_g, thanks for the information about wpe-webkit-mir-kiosk but it also doesn’t work.
logs from wpe-webkit-mir-kiosk http://dpaste.com/2GYG5EG
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Which pi4 image are you using exactly ?
@ogra this one: http://cdimage.ubuntu.com/ubuntu-core/18/stable/current/ubuntu-core-18-arm64+raspi4.img.xz
@malt thanks, I just wanted to make sure you are not using my experimental image from the pi4 thread in this forum (i sadly cant edit the posts there to remove the links).
@alan_g the EGL errors look identical to what i see on my image with any XWayland app
Ack, we should start with checking if any EGL clients work. (The mir-test-tools snap has what we need for that.)
mir-test-tools tested on Pi4 4GB RAM:
sudo snap run mir-test-tools.qt-test logs:http://dpaste.com/0XVZTV3
sudo snap run mir-test-tools.sdl2-test logs: http://dpaste.com/2CMW28N
sudo snap run mir-test-tools.gtk3-test logs: http://dpaste.com/1FCMMBW
sudo snap run mir-test-tools.performance-test logs: http://dpaste.com/0ZRFV63
sudo snap run mir-test-tools.basic-test logs: http://dpaste.com/1ZPG1KA
sudo snap run mir-test-tools.smoke-test logs: http://dpaste.com/2ZAMYTE
sudo snap run mir-test-tools.stress-test logs: http://dpaste.com/1ZW27BX
So, there appear to be two problems here, a surface one and an underlying one.
The surface one is that EGL clients are failing, because for some reason the software rasteriser is failing to work against Mir.
The underlying one is that accelerated GL isn’t working at all, and we’re falling back to the software rasteriser. We appear to have the relevant kernel module and DRI driver built and installed, but it is failing to load. I will continue to investigate this.
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Please let me know if I can help with debugging – Pi 4 w/ 4GB available – and/or if wpe-webkit-mir-kiosk (which I maintain) requires changes to work properly on the Pi 4. 
I think I have a similar/the same issue.
I have a snap of an Electron-based kiosk application (based on the electron-kiosk tutorial) which works on the Raspberry Pi 3 (ubuntu-core-18-armhf+raspi3) but not the Raspberry Pi 4 (ubuntu-core-18-armhf-raspi4).
On the Pi 3 the logs show:
Mar 25 17:44:05 localhost systemd[1]: Started Service for snap application krellian-kiosk.krellian-kiosk. Mar 25 17:44:11 localhost systemd[1]: Stopping Service for snap application krellian-kiosk.krellian-kiosk… Mar 25 17:44:11 localhost systemd[1]: Stopped Service for snap application krellian-kiosk.krellian-kiosk. Mar 25 17:44:11 localhost systemd[1]: Started Service for snap application krellian-kiosk.krellian-kiosk. Mar 25 17:44:20 localhost krellian-kiosk.krellian-kiosk[5940]: glamor: EGL version 1.4: Mar 25 17:44:24 localhost krellian-kiosk.krellian-kiosk[5940]: Starting services on port 8080…
On the Pi 4 the logs show:
Mar 25 16:34:58 localhost systemd[1]: Started Service for snap application krellian-kiosk.krellian-kiosk. Mar 25 16:35:18 localhost krellian-kiosk.krellian-kiosk[6452]: glamor: EGL version 1.4: Mar 25 16:35:18 localhost krellian-kiosk.krellian-kiosk[6452]: (EE) Mar 25 16:35:18 localhost krellian-kiosk.krellian-kiosk[6452]: Fatal server error: Mar 25 16:35:18 localhost krellian-kiosk.krellian-kiosk[6452]: (EE) wl_display@1: error 2: no memory Mar 25 16:35:18 localhost krellian-kiosk.krellian-kiosk[6452]: (EE) Mar 25 16:35:18 localhost krellian-kiosk.krellian-kiosk[6452]: i3: Cannot open display Mar 25 16:35:18 localhost krellian-kiosk[6709]: cannot open display: :42
Is there an existing bug report tracking this issue or should we file one?
Application source code: https://github.com/krellian/kiosk Application builds: https://build.snapcraft.io/user/krellian/kiosk
Side note: Where can I send a pull request for the tutorial? A recent change to the Snapcraft build process broke this tutorial and it now needs an extra npm install in the override-build section.
Thanks
Here’s the “source” of the tutorial: https://discourse.ubuntu.com/t/make-a-html5-electron-based-kiosk-snap/13992
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Has anyone had any success in running any mir-kiosk apps on the RPi4 yet?
I’m not sure if this helps, or if you were looking for a more complete answer. But yes, there are some kiosk snaps that work on RPi4.
mir-kiosk-apps works.
mir-kiosk-scummvm sorta works.
mpv-kiosk sorta works.
Many of the tests from mir-test-tools seem to work.
As mentioned above:
That’s not so much a mir-kiosk problem as the Ubuntu Core graphics stack not (yet) supporting RPi4 for clients.
well, the general ubuntu stack … i dont think it works on classic installs either 
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We’re receiving a lot of requests from users asking when they can use the RPi4 for our smart mirror software (which uses our wpe-webkit-mir-kiosk snap on mir-kiosk). At the moment, we advise to buy the 3B, but the Pi 4 with 2GB RAM costs just a few bucks more.
Is there a rough timeframe for GL support on the Pi 4? Pointers to what needs to be done? Glad to help with testing (we have a Pi 4 here), and willing to help out otherwise – although I can’t offer substantial GL stack knowledge 
We have the same problem. Did you find any workaround?
The kernel fixes are still WIP:
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Hello @alan_g,
Can you please share what would be the way forward for rpi4?
Is there any plan to have above fixes for 18.04 in near future or do we have to switch to core 20?