Description of problem: Pass the /dev/parport0 to guest does not work with qemu-kvm Version-Release number of selected component (if applicable): libvirt 0.9.4 How reproducible: always Steps to Reproduce: 1. Configure /dev/parport0 <parallel type='dev'> <source path='/dev/parport0'/> <target port='0'/> </parallel> 2. Start guest and try to use the parallel port. Actual results: Not working Expected results: Working Additional info: The commandline produced by libvirt looks like this: -chardev tty,id=charparallel0,path=/dev/parport0 -device isa-parallel,chardev=charparallel0,id=parallel0 The first parameter is "tty". Should not it be "parport"? If I start the qemu in the commandline with tty replaced with parport it is working as expected. I will try to provide a patch that fix this issue. There was also a post in the libvirt-users mailinglist from an other users a couple of months ago: https://www.redhat.com/archives/libvirt-users/2011-September/msg00095.html
(In reply to comment #0) > The first parameter is "tty". Should not it be "parport"? > If I start the qemu in the commandline with tty replaced with parport it is > working as expected. > > I will try to provide a patch that fix this issue. Thanks; if you have questions, I'm sure folks on the list would be glad to answer them.
Created attachment 586043 [details] Patch that fixes the wrong commandline generated by libvirt for qemu parallel port support Not sure if this is fix is very clean, but for my case it works. Perhaps it should also be check if similar problems / patches are required for other chardev backends.
Would you mind sending the patch to libvir-list as well?
Patch posted to the libvir-list.
Fix will be in 0.9.13. commit 7508338ff3b75b39ee9654e3d83bc58c858dc92a Author: Beat Jörg <Beat.Joerg> Date: Wed May 23 07:50:02 2012 +0200 Fix for parallel port passthrough for QEMU I came across a bug that the command line generated for passthrough of the host parallel port /dev/parport0 by libvirt for QEMU is incorrect. It currently produces: -chardev tty,id=charparallel0,path=/dev/parport0 -device isa-parallel,chardev=charparallel0,id=parallel0 The first parameter is "tty". It sould be "parport". If I launch qemu with -chardev parport,... it works as expected. I have already filled a bug report ( https://bugzilla.redhat.com/show_bug.cgi?id=823879 ), the topic was already on the list some months ago: https://www.redhat.com/archives/libvirt-users/2011-September/msg00095.html