USB-Serial loses connection immediately in new linux (kernel 4.12.14) [closed]

Question

I upgraded my Linux(Opensuse from 42.3 to 15) but encountered new bug. When I connect my USBserial dongle it shows ttyUSB0 in dev folder and immediately disconnected and goes from dev list.

It seems all from 'brltty' but I don't know what is this doing.

My dmesg output is:

[  960.719371] usb 1-4: new full-speed USB device number 5 using xhci_hcd
[  960.898481] usb 1-4: New USB device found, idVendor=10c4, idProduct=ea60
[  960.898483] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  960.898484] usb 1-4: Product: CP2102 USB to UART Bridge Controller
[  960.898485] usb 1-4: Manufacturer: Silicon Labs
[  960.898486] usb 1-4: SerialNumber: 0001
[  961.424298] usbcore: registered new interface driver usbserial
[  961.424309] usbcore: registered new interface driver usbserial_generic
[  961.424318] usbserial: USB Serial support registered for generic
[  961.425223] usbcore: registered new interface driver cp210x
[  961.425235] usbserial: USB Serial support registered for cp210x
[  961.425254] cp210x 1-4:1.0: cp210x converter detected
[  961.426718] usb 1-4: cp210x converter now attached to ttyUSB0
[  961.679984] usb 1-4: usbfs: interface 0 claimed by cp210x while 'brltty' sets config #1
[  961.680703] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0
[  961.680716] cp210x 1-4:1.0: device disconnected

ThanX

Policeman

Removing 'brltty' seems solve problem but don't know is this right solution and removing that package my harm my linux? – Policeman

Are you blind? The brltty process is intended for braille display hardware. That is why it grabs serial ports. – Spur

Thank god I am not blind yet. I just install default packages of linux. – Policeman

It seems the default packages of linux should be change or some sort of config file should be with brltty package. The config file for dedicating one or some port to braille display hardware and not connect automatically to all USB-serial. – Policeman

Answer 1

I had a similar issue with connecting an M5Stack Core device. At a point it stopped being visible to UIFlow and other provisionig tools for it.

After several days of mostly frustration, I googled that line from the dmesg output that mentions the 'brltty'. So a guy on the Linux Mint forum obviously figured it out. I removed 'brltty' in synaptic and it never gave me any indications of any other dependencies, hence it seemed safe for removal. Everything was downhill from there.

Rosetta

I have spent few hours to try to figure out why my arduino can't be programmed anymore. After trying all kind of arduino related tricks, tools, I turned to the USBs and thanks to some other SO answers I have managed to monitor udev changes where I finally saw that my linux actually sees the USB, but then it gets removed right after it appears. Then I found this question and your comment about the brltty package. I removed it and all works now. Thank you! – Ki

removing the brltty fixed the issue as the @Rosetta suggested, apt-get autoremove brltty. Thanks. – Salaried

removing brltty also fixed it for me, thanks a lot! sudo apt remove brltty -y for the lazy ones... – Crissycrist

Answer 2

well I have ubuntu 22.04 same problem so removed "britty" which is for the blind via synaptic and now can connect to my radios no problem so far maybe it shouldn't be default?

Atrium

same here. Removing brltty soves it thankfully. I have raised this bug report, please click on it to indicate that you are also affected so if the status can be updated to confirmed: bugs.launchpad.net/ubuntu/+source/brltty/+bug/1970408 – Scorpion

Maybe it still has to be a default but they need to fix it not to interfere with the USB interface in such a way. – Rosetta

Please edit to add some strategic punctuation. – Poison