Hi Greg, thank you for your reply. The kernel version I am using is the one currently shipped with the latest release of Ubuntu 20.04 (LTS). They will certainly upgrade the kernel in the future: if you tell me that the problem does not exist in a successive kernel release, I will post the info and close the issue. You ask me "Where is your usb-to-serial device here?". The point is that nothing appears in the lsusb related to the device, although it is plugged in (the device receives power). Plugin/unplugging the device does not result in any output in syslog/dmesg. I tried to manually insert the driver, with no result. The device is not discovered at all, but it was (and worked perfectly) in the previous Ubuntu release (19.10), and I just guess the kernel was 5.3.0-64-generic. So I have no clue..., and it would be helpful to have a way to obtain any sort of. Thank you, Augusto Il giorno mar 5 gen 2021 alle ore 16:26 Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> ha scritto: > > 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
