Well it took me longer than i hoped but i have managed to forward port icenowys code for TVE on the H2+/H3 to mainline armbian. It seems to work totally fine, with a few caveats.
First: Sample images of it in action -> https://imgur.com/a/vXQEM
Second: the patch itself -> https://github.com/stevenj/h3-tve/tree/v0.0.11
Third a prebuilt image for Orange Pi Zero: -> https://github.com/stevenj/h3-tve/releases/tag/v0.0.11
Howto:
just put the patch into userpatches for the sunxi-next kernel, and build. it should apply cleanly. Its for H2+/H3. I have only tried it on a orange pi zero, but it should work on all H2+/H3 boards.
You then need to edit /boot/armbianEnv.txt
add tve to overlays to enable it. the driver will only run and enable tv out when the tv out devices are specifically enabled, so i created an overlay which does this. If you want to turn TV out off, just remove tve from the overlays line.
My armbianEnv.txt overlays looks like this:
overlays=usbhost2 usbhost3 tve
If you want copious amounts of DRM debug info in your logs, add this as well:
extraargs=drm.debug=0xF
Its not needed, unless you really want the debug info.
Notes:
1. The default mode is PAL, with 720x576 resolution. Thats outside of normal PAL displayable area, and so the screen overscans.
I dont know how to correct this, although its mostly just annoying with terminals.
I also don't know how to change the video mode to NTSC.
2. The standard font is a bit thin for composite video, and causes slight strobing and color impurity. Its because PAL needs pixels to be a certain MINIMUM width or color information can not be properly encoded.
A way to resolve this is use :
# apt-get install fbterm
...
$ fbterm -s 20
This will run a terminal which is easy to change the font, and pick a bigger one. its much easier to read. Look at the help for fbterm to work out everything it can do.
3. I used the program "fim" to display the test images. there are others for doing stuff on the terminal.
4. I haven't tried X. I am not interested in running an X terminal on a TV, but it should probably work fine.
Other than that it all seems good. I originally tested my hardware with the legacy kernel, and the image quality from this patch seems superior to what the legacy kernel produces. (legacy was noisy)
The only other thing you need to know is Orange Pi Zero is missing filter circuity from its Composite Output, the most important thing you need to do is put a 50 ohm resistor between the signal and GND. i soldered one inside my RCA connector, it fits fine and isn't too difficult. IF you don't do this the image will bloom and look like total crap, so you have been warned.
As this patch allows TVE to be enabled/disabled through use of the Device Tree overlays, i think it should be fine if the Armbian devs want to include it. I am happy to clean out some of the debug messages i added if they are interested in making a standard part of the build. If not, its easy enough to build your own image, just follow the guides on how to rebuild armbian.
EDIT: I need to mention, all props go to Icenowy Zheng who wrote the original driver. I just tweaked the device tree stuff and got it in a state where it can apply cleanly to the armbian mainline kernel and build system.
Original code is here:
https://github.com/Icenowy/linux/tree/tve-v2
