Error message when trying to run kmscube

Products Support DragonBoard410c
#1

Hi All,

I tried to run kmscube on Dragonboard 820 and 410, and got the same error message in both cases:
“failed to set mode: Permission denied”

Has anyone encountered this before?

Thanks,
Eran

#2

that’s very odd…
just a couple of things, what debian build are you using and where did you get the source for kmscube ?

#3

On the 410 it’s build 283, on the 820 build 173, both were updated (apt-get update and apt-get upgrade).
I tried to use the build that comes with the build, I haven’t built from source.

#4

I have never tried the kmscube from the build, can you try and compile this source: https://github.com/robclark/kmscube
this basically is the unmodified aka vanilla source.

#5

hi,

I think you are trying to run kmscube while a GUI (X , or weston) is already running. It won’t work. kmscube will grab the graphics card and manage it, so you have to stop X/GUI first.

in our Debian images we use the SDDM login manager, so you can kill the GUI with

systemctl stop sddm

Alternatively, if you want to permanently boot to FB console (non graphics) instead of GUI:

systemctl set-default multi-user.target
#6

Thank you so much, @anon91830841, That worked beautifully!!

#7

Hi @anon91830841
I am new to graphics programming. I have a question on kms/gbm
Is there a way we can use kmscube or any other simple application that can display a window on top of the existing GUI?
All I want to achieve is without killing the GUI, I want to make an overlay window using gbm_surface_create_with_modifiers and eglCreateWindowSurface