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Framebuffer notes
I wasted a lot of time wondering why /dev/graphics/fb0 was 1280x33 (and trying to hack modelines, etc). Answer: its the black grab bar at the top of Android's GUI (with the clock, wifi indicator, etc). I had an xterm running in 1280x33 before I clued in!
On my Galaxy Note 8, fb3 is the correct framebuffer. Not sure what fb1 and fb2 are!
Meefik suggests "cat /dev/random > /dev/graphics/fb0". This is useful to see which ones are connected to something but it doesn't tell you what is what. I used trial-and-error.
On my Galaxy Note 8, I have to use "Stop" for framebuffer to work. (TODO: maybe Pause, but "Don't Freeze" definitely doesn't work).
In the same page where you can change which fbX to use, there is a setting "Display" (or similar, I don't have my device with me atm). This setting just changes the X11 display server (notably the "0" in /var/log/Xorg.0.log). So fiddling this setting is unlikely to make your framebuffer work!
After installing. I use the following workflow for debugging framebuffer. Maybe this will help someone else.
- Start LinuxDeploy and then start your distro.
- ssh in from my laptop.
- "killall X" (or maybe Xorg)
- modify /home/android/.xnitrc and /etc/X11/xorg.conf
- "xinit"
- ctrl-C to kill X, back to step 4, repeat.
All the while, in another ssh session, you can look at /var/log/Xorg.0.log
I also did "sudo -i", "chmod 666 /etc/X11/xorg.conf" so that I could edit that file as user android. The xorg.conf can get overwritten/edited by Linux Deploy (maybe the "Reconfigure" button?). Keep a backup if you edit it.
TODO: Possibly removing the "# linux deploy" comments (e.g., from /dev/graphics/fb0) will prevent it from modifying them?