ch340 USB/serial - brltty interference

[Matěj Pavel]

the CH340 does show up in lsusb:
'Bus 001 Device 005: ID 1a86:7523 QinHeng Electronics CH340 serial converter'

but does not show up in /dev if brltty is installed on the system.

Device does show up as /dev/ttyUSB0 after removing brltty and rebooting.

tested systems:
Ubuntu 22.04.1 (live USB) - problem present
Linux Mint 21 (fresh install, updated) - problem present

ubuntu-bug does not recognise brltty as an ubuntu package and thus refuses to collect data.

The CH340 is a very common USB/serial converter chip used in cheap 3D printers and microcontroller development boards.
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5json: {
CurrentDesktop: X-Cinnamon
DistroRelease: Linux Mint 21
InstallationDate: Installed on 2022-09-20 (0 days ago)
InstallationMedia: Linux Mint 21 "Vanessa" - Release amd64 20220726
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
Package: brltty 6.4-4ubuntu3 [origin: Ubuntu]
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 5.15.0-48.54-generic 5.15.53
Tags: third-party-packages vanessa
Uname: Linux 5.15.0-48-generic x86_64
UnreportableReason: This does not seem to be an official Linux package. Please retry after updating the indexes of available packages, if that does not work then remove related third party packages and try again.
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dialout dip input lpadmin plugdev sambashare sudo
_MarkForUpload: True

[Chris Guiver (guiverc)]

Thank you for taking the time to report this bug and helping to make Ubuntu better.

Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1990357

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

Please note: `ubuntu-bug`, `apport` & bug reporting tools are provided with Ubuntu by default, many require manual addition for some releases of downstream OSes based on Ubuntu (eg. Linux Mint). You should check with your distribution first.

additional note: If you don't wish to add apport tools to Linux Mint, please perform it using the Ubuntu live media you mention... Thanks for helping to make Ubuntu better

[Matěj Pavel (matej101)]

apport information

[Matěj Pavel (matej101)]

apport information

[Matěj Pavel (matej101)]

apport information

[Matěj Pavel (matej101)]

apport information

[Matěj Pavel (matej101)]

note that I did not install brltty. It was present from the start on both Mint 21 and Ubuntu 22.04. apport reporting it as third party may be another bug.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Bill Turner, wb4alm (wb4alm)]

Under UBUNTU 22.04.1 brltty PREVENTED me from using a USB->serial converter to access a remote piece of equipment. Once uninstalled, I had full access to the remote device.

Under LINUX MINT 21, you cannot uninstall brltty, and it did --NOT-- create a problem with the remote device, other than a name change to the port.

Under UBUNTU 22.04.1, the port is named /dev/ttyUSB0
Under Linux Mint 21, the port is named /dev/ttyS0

[ihor lys (ihor-lys)]

This bug still exists even for recent installations of 22.04 LTS. Thats not actually surprising, but the path needed to create this bug is.

Capturing the serial converter USB device generically as has been shown, is a MAJOR breakdown of proper etiquette at least, and a don't care attitude on the part of the Braille device manufacturers, those writing of the udev rules, and those allowing that into the distributions. This was a coordinated effort amongst multiple people to ignore at least best practices in the name of "accessibility". I can only imagine what could be done if someone wanted to be malicious.