udev rules should blacklist the exart / vizzini hardware UART on the Atlys from the USB-CDC ACM driver (and maybe warn about the condition)

[mithro]

The USB-CDC ACM driver is not compatible with the exart / vizzini hardware USB UART on the Atlys. It will successfully bind to the USB device and then appear to not work.

To get this UART to work you instead need to install the exart / vizzini driver.

The udev rules should prevent the USB-CDC ACM driver from binding to the exart using the USB IDs see https://github.com/timvideos/HDMI2USB-mode-switch/blob/master/udev/98-hdmi2usb-atlys.rules#L28-L34

HDMI2USB-mode-switch should also warn / complain about the USB-CDC ACM driver being bound to the exart device. There already is a horrible hack for dealing with this. The .drivers() attribute should already have the info about which module is bound to the device.

[mithro]

apt-add-repository ppa:timvideos/fpga-support
apt install fxload vizzini-dkms

[mithro]

https://github.com/mithro/exar-uart-driver

[mithro]

@shenki - What happened to the driver which was suitable to send upstream for this stupid hardware uart?

[mithro]

@shenki - My email lot says to look here -> https://github.com/shenki/linux/tree/vizzini

[mithro]

@shenki - IIRC We got to the driver working but wanted to refactor things slightly. I'm pretty sure we wanted to move this hack -> https://github.com/shenki/linux/blob/vizzini/drivers/usb/serial/usb-serial.c#L818-L857 into the probe function because the vizzini module has similar functionality at https://github.com/shenki/linux/blob/vizzini/drivers/usb/serial/vizzini.c#L297-L321