Public bug reported: when booting UC20 on a Pi4 the screen backlight is completely off and no signal is produced.
inspecting the boot a little closer it seems the necessary modules for bringing up the vc4 framebuffer are not included in the initramfs on ubuntu core. once they get loaded (after boot) the backlight and signal turn on. The initrd should include the modules and load them during boot. this is also required to bring any kind of bootsplash back to UC20 which is a reason all our digital signage customers currently hold back on going forward to UC20. the modules required are: ogra@ubuntu:~$ lsmod|grep vc4 vc4 290816 3 drm_kms_helper 225280 3 vc4 snd_soc_core 262144 1 vc4 snd_pcm 143360 5 vc4,snd_bcm2835,snd_soc_core,snd_pcm_dmaengine drm 565248 7 gpu_sched,drm_kms_helper,v3d,vc4 the loading during boot in the journal is shown below: ogra@ubuntu:~$ sudo journalctl -b | grep vc4 Apr 01 17:23:45 ubuntu kernel: vc4-drm gpu: bound fe600000.firmwarekms (ops vc4_fkms_ops [vc4]) Apr 01 17:23:45 ubuntu kernel: fb0: switching to vc4drmfb from simple Apr 01 17:23:45 ubuntu kernel: [drm] Initialized vc4 0.0.0 20140616 for gpu on minor 1 Apr 01 17:23:45 ubuntu kernel: vc4-drm gpu: fb0: vc4drmfb frame buffer device ** Affects: linux-raspi (Ubuntu) Importance: Undecided Status: Confirmed ** Affects: linux-raspi (Ubuntu Focal) Importance: Undecided Status: New ** Affects: linux-raspi (Ubuntu Groovy) Importance: Undecided Status: New ** Affects: linux-raspi (Ubuntu Hirsute) Importance: Undecided Status: Confirmed ** Description changed: when booting UC20 on a Pi4 the screen backlight is completely off and no signal is produced. inspecting the boot a little closer it seems the necessary modules for bringing up the vc4 framebuffer are not included in the initramfs on ubuntu core. once they get loaded (after boot) the backlight and signal turn on. The initrd should include the modules and load them during boot. - this is also required to bring any kind of bootsplash back to UC20 with + this is also required to bring any kind of bootsplash back to UC20 which is a reason all our digital signage customers currently hold back on going forward to UC20. the modules required are: ogra@ubuntu:~$ lsmod|grep vc4 vc4 290816 3 drm_kms_helper 225280 3 vc4 snd_soc_core 262144 1 vc4 snd_pcm 143360 5 vc4,snd_bcm2835,snd_soc_core,snd_pcm_dmaengine drm 565248 7 gpu_sched,drm_kms_helper,v3d,vc4 the loading during boot in the journal is shown below: ogra@ubuntu:~$ sudo journalctl -b | grep vc4 Apr 01 17:23:45 ubuntu kernel: vc4-drm gpu: bound fe600000.firmwarekms (ops vc4_fkms_ops [vc4]) Apr 01 17:23:45 ubuntu kernel: fb0: switching to vc4drmfb from simple Apr 01 17:23:45 ubuntu kernel: [drm] Initialized vc4 0.0.0 20140616 for gpu on minor 1 Apr 01 17:23:45 ubuntu kernel: vc4-drm gpu: fb0: vc4drmfb frame buffer device -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1914608 Title: no console during boot on UC20 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/1914608/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs