Good news! I finally got it working! I can get `modeset` to display a test pattern. In the absence of other guides, I thought I would post here what I did to accomplish this.


Modify the device tree! I added the following to the end of my `rk3506-luckfox-lyra-sd.dts`:

/**********DISPLAY ...

One more thing to add -- I have confirmed that my scope is not (entirely) reading dud values. I rebuilt the kernel with the trace option and found that the modetest, by way of the SPI controller, is in fact sending the wrong data.

modetest-1679 [002] ..... 147.744264: spi_transfer_start: spi1.1 ...

Thank you for that. I did realize the config.txt is specific to RPi after a short while. I'm aiming for the TinyDRM driver since many sources say the FBTFT driver is deprecated. If all else fails I'll go with FBTFT but I'm hoping with some of my own research we all can find a solution.

I'm able to ...

I know I'm asking for a lot of trouble here, but I'll ask anyway.

I see that, out-of-box, Luckfox Lyra has support for a few DSI displays -- a few more than Raspberry Pi has (wink). However, I'm trying to use something physically smaller than 2.8". I have a few ST7789s lying around, and I know for ...

Sorry I missed the previous responses. You can muck around with the device tree and set the LED behavior "none" instead of disabling it entirely. I found in <sdk_loc>/kernel-6.1/arch/arm/boot/dts/rk3506-luckfox-lyra.dtsi, there's a section that says

leds: leds {
compatible = "gpio-leds";
work ...

To disable the LED using sysfs as suggested previously:
echo 'none' > /sys/devices/platform/leds/leds/work-led/trigger

There appear to be other modes of LED operation, i.e. caps lock/num lock/etc. The available options can be found by running:
cat /sys/devices/platform/leds/leds/work-led/trigger ...