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Message #169679
[Bug 1542862] Re: pl2303h and ftdi serial port bug
** Tags added: xenial
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https://bugs.launchpad.net/bugs/1542862
Title:
pl2303h and ftdi serial port bug
Status in linux package in Ubuntu:
Incomplete
Bug description:
When developing an application using serial ports, behaviour between
process restarts is undefined for particular usb serial port chipsets.
Tested chipsets to fail are:
* pl2303H
* ftdi
Tested chipsets to work are:
* 16550A
* pl2303ra
Attached is a minimal test program to recreate the issue. The program
needs to run twice, the first to create the problem, the second
instance that shows the problem. See the comments at the beginning of
the test program to see expected output and observed output.
You'll need the device under question attached and running as the
receiver in the test program and a NULL modem cable (3 wire). Easiest
to show the problem if you have two of the same USB devices attached
and execute the command with "./a.out /dev/ttyUSB0 /dev/ttyUSB1".
Note, flushing, and other workarounds haven't worked, only physically
removing and reinserting the problematic devices between runs (in
particular, the device that is receiving the data over the serial
port).
As there appears to be data in a buffer between runs that can't be
properly flushed, I can't say if this is a potential security issue or
not.
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.19.0-49-generic 3.19.0-49.55~14.04.1
ProcVersionSignature: Ubuntu 3.19.0-49.55~14.04.1-generic 3.19.8-ckt12
Uname: Linux 3.19.0-49-generic i686
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: i386
CurrentDesktop: Unity
Date: Sun Feb 7 15:28:42 2016
InstallationDate: Installed on 2016-02-04 (2 days ago)
InstallationMedia:
SourcePackage: linux-lts-vivid
UpgradeStatus: No upgrade log present (probably fresh install)
---
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: i386
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: jcurl 2149 F.... pulseaudio
CurrentDesktop: Unity
DistroRelease: Ubuntu 14.04
HibernationDevice: RESUME=UUID=f20d2ed2-18be-4b14-b4f2-d28d8962a377
InstallationDate: Installed on 2016-02-04 (31 days ago)
InstallationMedia:
MachineType: LENOVO 64577WG
NonfreeKernelModules: nvidia
Package: linux (not installed)
PccardctlIdent:
Socket 0:
no product info available
PccardctlStatus:
Socket 0:
3.3V
32-bit
PC Card
ProcFB:
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-49-generic root=UUID=77ac576d-595e-4ec1-ae5e-3791f7cfe23b ro quiet splash
ProcVersionSignature: Ubuntu 3.19.0-49.55~14.04.1-generic 3.19.8-ckt12
RelatedPackageVersions:
linux-restricted-modules-3.19.0-49-generic N/A
linux-backports-modules-3.19.0-49-generic N/A
linux-firmware 1.127.20
Tags: trusty
Uname: Linux 3.19.0-49-generic i686
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 04/08/2010
dmi.bios.vendor: LENOVO
dmi.bios.version: 7LETC7WW (2.27 )
dmi.board.name: 64577WG
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr7LETC7WW(2.27):bd04/08/2010:svnLENOVO:pn64577WG:pvrThinkPadT61p:rvnLENOVO:rn64577WG:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 64577WG
dmi.product.version: ThinkPad T61p
dmi.sys.vendor: LENOVO
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References