Problem with the CH341 driver in Ubuntu 20.04

[Thadeu Lima de Souza Cascardo]

On Tue, Jan 05, 2021 at 05:30:45PM +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).
> 

So, if I understand it, it did work before you upgraded. Can you try booting
with one of the old 5.3 kernels, and send the output of lsusb?

Please do send that in a bug in launchpad, where we can more easily track the
status of the bug.

> This is the kernel I am using:
> 
> ===
> $ uname -r
> 5.4.0-58-generic
> ===
> 
> 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 at 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 at Legion:~$ sudo modprobe ch341
> [sudo] password di augusto:
> augusto at 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

The device does not seem present, does it? So, I wonder if this is plugged in a
hub, and the hub code is broken, not the serial driver. Otherwise, which one of
these is the device you are trying to match?

> augusto at Legion:~$ lsmod | grep ch34
> ch341                  20480  0
> usbserial              53248  1 ch341
> ===
> 
> Without this module it is impossible to work with a relevant number of
> SBC devices, besides the named Wemos D1 Mini.
> 
> Trying to solve the problem I also downloaded and installed the module
> source from https://github.com/juliagoda/CH341SER and compiled on my
> PC, after removing the "secure boot" feature.
> 

You didn't say it, but I assume it didn't work either. Is that correct?

Thanks.
Cascardo.

> Thank you for any help.
> 
> Note: I originally posted this question on AskUbuntu
> (https://askubuntu.com/questions/1304116/problem-with-the-ch341-driver-in-ubuntu-20-04),
> but with no answer after 40+ views. I bounced to the
> linux-usb at vger.kernel.org maillist which suggested submitting the
> problem to the Ubuntu kernel team. Here I am...
> 
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