🪲[BUG] Breaks when used with SPI (st7735 QMK)

[raghur]

Describe the bug you encountered:
I'm using this with a QMK converter; tried to hook up a st7735_spi driver with quantum painter and found that when the USB device is connected, the keyboard & display both stop working.

USB enumeration works correctly but neither the display, nor the keyboard work.

Without the keyboard connected, the display works;

If I do not connect the to the SPI device, the usb keyboard works fine.
...

What did you expect to happen instead?

Both the LCD display and physical keyboard connected to the USB hub work
...

What actually happened in your case?

USB enumeration works correctly but neither the display, nor the keyboard work.
Without the keyboard connected, the display works;
If I do not connect the to the SPI device, the usb keyboard works fine.

If I delay the initialization of the SPI connection by a few seconds, then for those few seconds, the keyboard works fine and keyboard reports are received.

...

Additional information

1. Using QMK
2. tinyusb master
3. this project at master.
   https://github.com/raghur/adafruit_rp2040_usbh/tree/759ea3097d089acad65517d01dec5a5a7a68d712

branch: https://github.com/raghur/adafruit_rp2040_usbh/tree/st7735, commit: 759ea3097d089acad65517d01dec5a5a7a68d712

---

[raghur]

This is likely caused by DMA conflict since QMK uses chibios;

Setting pio_cfg.tx_ch = 11; is a workaround that partially addresses it (not foolproof); with that in place, the display initializes properly but there is still some other conflict since the keyboard itself is never usable.