Thanks, I was trying to run android in vga monitor via vga666 resistor circuit. I created the relevant pull request in your pie-device-brobwind-rpi3-drm_hwcomposer repository in github. With that commit and relevant kernel panel driver (I'm using simple-panel) and device overlay I successfully run a...

Is there any way to change kernel without compiling the whole project? I compiled the kernel but but how to make that into a boot.img easily?

Okey first I wasted couple of hours bcz I had CONFIG_DRM_PANEL_SIMPLE disabled in my kernel .config :shock: :oops: I can enable DPI and control its timing/freq/res by editing drivers/gpu/drm/panel/panel-simple.c and recompiling kernel. :ugeek: The problem is now how to do what display_default_lcd=1 ...

fruitoftheloom wrote: ↑

Fri Jul 26, 2019 4:46 am

"Panel" is via the DSi Connector in this context, nothing to do with VGA, which already has a solution:

https://uk.pi-supply.com/products/gert- ... spberry-pi

No my friend, you missed the context That vga666 adapter needs DPI, and DPI is what we were discussing.

So the panel driver is something like https://github.com/raspberrypi/linux/blob/rpi-4.19.y/drivers/gpu/drm/panel/panel-simple.c, and indeed that is the one that the Kippah overlay is loading. If you look at the overlay, it is saying the panel is a "ontat,yx700wv03". In the driver that str...

I see, the scenario becomes more clear now. I think this should be mentioned in https://www.raspberrypi.org/documentation/hardware/raspberrypi/dpi/README.md . Just a note that "Instructions in this page won't work with vc4-kms-v3d" There is an overlay for running a DPI display from vc4-kms...

Thank you both for the quick answer. I was having trouble with vga666 / DPI Display. dpi_ related entries in config.txt wasn't being applied. Landed here from google. Kinda off-topic, but problem is solved by switching to vc4-fkms-v3d from vc4-kms-v3d.

Kinda offtopic but what is the difference between vc4-fkms-v3d and vc4-kms-v3d?

Thank you very much for the explanation. I'll discard the DAC0808 idea and use resistors. I'll try two in series to make the correct value, ex: 3.3K+680 = 4K, 6.8K+1.2K = 8K etc.... If i don't find exact 2K,4K,8K etc.. values.

Can anyone tell me (or direct me to some spec) about the DAC conversation timing? Using a resistor network will be very fast but its hard to find accurate and multiplier value resistors. I'm thinking about using three DAC0808. According to Datasheet its 150 ns. Is that okey for vga?