Re: Problem with the CH341 driver in Ubuntu 20.04

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Jan 05, 2021 at 04:14:14PM +0100, Augusto Ciuffoletti wrote:
> I run into this problem trying to program an ESP8266 board, which uses
> the CH341 chip in the programming interface as a USB-to-Serial
> interface. The problem appeared after an upgrade from Ubuntu 19.10 to
> 20.04 (that I carried out one week ago).
> 
> This is the kernel I am using:
> 
> ===
> $ uname -r
> 5.4.0-58-generic

That's an old kernel, you should get support from your distro if you
want to stick with that, but:

> ===
> 
> When I connect the ESP8266 board (a Wemos D1 mini) to the USB there is
> no activity on the syslog (or dmesg), and the kernel module is not
> loaded. In fact I do not see the /dev/ttyACM0 device in the /dev
> directory and no useful device appears in the Arduino GUI.
> 
> I have found the module in the kernel tree but, even forcing the
> installation, nothing happens:
> 
> ===
> augusto@Legion:~$ ls
> /usr/lib/modules/5.4.0-58-generic/kernel/drivers/usb/serial/ch*
> /usr/lib/modules/5.4.0-58-generic/kernel/drivers/usb/serial/ch341.ko
> augusto@Legion:~$ sudo modprobe ch341
> [sudo] password di augusto:
> augusto@Legion:~$ lsusb
> Bus 002 Device 002: ID 05e3:0626 Genesys Logic, Inc. USB3.1 Hub
> Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
> Bus 001 Device 003: ID 13d3:56a6 IMC Networks Integrated Camera
> Bus 001 Device 005: ID 0cf3:e500 Qualcomm Atheros Communications
> Bus 001 Device 006: ID 046d:c517 Logitech, Inc. LX710 Cordless Desktop Laser
> Bus 001 Device 004: ID 093a:2510 Pixart Imaging, Inc. Optical Mouse
> Bus 001 Device 002: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Where is your usb-to-serial device here?  Are you sure it's actually
working?  I don't see it in the list of devices, which is a pretty good
reason why the serial driver isn't working :)

Try looking in the kernel log when you plug the device in, perhaps it
says something?

thanks,

greg k-h