ch341 USB-Serial converter only receives, does not send
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Confirmed
|
Undecided
|
Unassigned |
Bug Description
This device works flawlessly on Windows XP with native driver, both as a physical machine or inside a VM. It appears on XP's device management as "USB 2.0" name.
On Ubuntu, Shorting pins 2 and 3 of DB9 connector does not give back characters sent (no echo), nor typed strings are sent to other RS232 devices, despite of communication settings. Characters from remote devices are correctly received. Using a null modem cable to other RS232 terminal shows that the local terminal receives, but does not transmit.
Its worth to mention: passing through the device to a guest virtual machine (KVM) running Windows XP makes it work correctly with XP driver inside the guest OS. Bringing back the device stops transmitting. Only receive works.
Tested with the version below:
NAME="Ubuntu"
VERSION="20.04.2 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.2 LTS"
VERSION_ID="20.04"
HOME_URL="https:/
SUPPORT_URL="https:/
BUG_REPORT_URL="https:/
PRIVACY_
VERSION_
UBUNTU_
Kernel:
Linux host 5.4.0-66-generic #74-Ubuntu SMP Wed Jan 27 22:54:38 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Device ID:
ID 4348:5523 WinChipHead USB->RS 232 adapter with Prolifec PL 2303 chipset
Modinfo:
filename: /lib/modules/
license: GPL v2
srcversion: 8F5F64E72BDA4E7
alias: usb:v4348p5523d
alias: usb:v1A86p7523d
alias: usb:v1A86p7522d
alias: usb:v1A86p5523d
alias: usb:v1A86p5512d
depends: usbserial
retpoline: Y
intree: Y
name: ch341
vermagic: 5.4.0-66-generic SMP mod_unload
sig_id: PKCS#7
signer: Build time autogenerated kernel key
sig_key: 1E:07:0D:
sig_hashalgo: sha512
signature: 50:CE:79:
Demsg entries:
usb 4-3: new full-speed USB device number 6 using ohci-pci
usb 4-3: New USB device found, idVendor=4348, idProduct=5523, bcdDevice= 2.50
usb 4-3: New USB device strings: Mfr=0, Product=0, SerialNumber=0
ch341 4-3:1.0: ch341-uart converter detected
usb 4-3: ch341-uart converter now attached to ttyUSB0
---
ProblemType: Bug
ApportVersion: 2.20.11-
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
/dev/snd/
CasperMD5CheckR
CurrentDesktop: KDE
DistroRelease: Ubuntu 20.04
InstallationDate: Installed on 2021-01-23 (50 days ago)
InstallationMedia: Kubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
MachineType: System manufacturer System Product Name
NonfreeKernelMo
Package: linux (not installed)
ProcFB: 0 VESA VGA
ProcKernelCmdLine: BOOT_IMAGE=
ProcVersionSign
RelatedPackageV
linux-
linux-
linux-firmware 1.187.10
RfKill:
Tags: focal
Uname: Linux 5.4.0-66-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip libvirt lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 11/18/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0502
dmi.board.
dmi.board.name: M5A78L-M PLUS/USB3
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev X.0x
dmi.chassis.
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.
dmi.modalias: dmi:bvnAmerican
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: System Product Name
dmi.product.sku: To Be Filled By O.E.M.
dmi.product.
dmi.sys.vendor: System manufacturer
Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https:/ /wiki.ubuntu. com/Bugs/ FindRightPackag e. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.
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