Archive for the ‘Ubuntu’ Category

Refreshing DNS-SD entries in Nautilus

September 22, 2013

When publishing a new DNS-SD service (aka Zeroconf, Bonjour, or Rendezvous) with Avahi (eg. by adding a .service file in /etc/avahi/service/), Nautilus sometimes doesn’t pick up changes made to the .service file, even though avahi-discover and avahi-browse have picked up the modifications. Killing and restarting Nautilus or Avahi doesn’t help either; the trick is to kill the gvfsd-network and gvfsd-dnssd processes, eg. with “killall gvfsd-network gvfsd-dnssd“.

Btw. for debugging, the gvfs-ls and gvfs-info command line tools are quite useful as they show the same info as displayed by Nautilus.

Oh, and if you want to use the “p=” parameter in a .service file for specifying the password for FTP: it’s not supported by Nautilus – only the “path” and “u” parameters are handled. If you really want to avoid any prompt when double-clicking an FTP share in Nautilus, either allow login as user anonymous on your FTP server (and specify “<txt-record>u=anonymous</txt-record>” in your .service file); or save the FTP password in the Gnome keyring.

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How to use Magic Sysrq on Lenovo Thinkpad Edge 11

March 2, 2012

The keyboard on Lenovo Thinkpad Edge 11 doesn’t have a Sysrq key anymore. As described at http://forum.notebookreview.com/thinkpad-edge-x1-x100e-x120e-sl-l/579456-no-insert-sysrq-keys-e220s.html#post7505261 there are Fn key combos to still get the functionality of these missing keys:

Fn+B = break
Fn+P = pause
Fn+S = sysrq
Fn+C = ScrLK
Fn+I = insert

To use Magic Sysrq key combos, this worked for me when using Ubuntu 11.04:

Press Alt, press Fn and S, release Fn and S, press the Sysrq command key.

For testing, the “h” command key is nice as it just prints some help text to kernel log. You can see in dmesg whether the key combo worked.

Installing Gnome DVB Daemon on Ubuntu Jaunty

June 3, 2009

In the last few months there have appeared various blog postings on Planet Gnome about a mysterious Gnome DVB Daemon (http://live.gnome.org/DVBDaemon). So I decided to give it a try on a Ubuntu Jaunty system with a DVB-T USB stick. The hardware itself was detected just fine by the kernel, and after some w_scan fiddling Totem also offered live watching; but I wanted to see if there’s something more user-friendly available, mainly for scanning and for EPG.

For the impatient: yes, after finishing the crazy building and installation steps, it looks quite promising.

So, installation time:

Install GStreamer 0.10.23

Install Gnome RTSP Server

Install newer libgee (Jaunty only ships 0.1.3)

Install Gnome DVB Daemon

Install data files etc.

  • sudo apt-get install dvb-utils

Move Totem plugin to correct location (well… at least, on my system Totem doesn’t look in /usr/local/lib/totem/plugins/):

  • sudo cp -r /usr/local/lib/totem/plugins/dvb-daemon/ /usr/lib/totem/plugins/

Fix Totem plugin (here, Totem failed to load the plugin with error message "Non-ASCII character '\xc3' in file /usr/lib/totem/plugins/dvb-daemon/dvb-daemon.py on line 1," etc.):

  • sudo gedit /usr/lib/totem/plugins/dvb-daemon/dvb-daemon.py
  • add this as first line in the file (before the Copyright line):

    # coding=utf8

For running Gnome DVB Daemon, have a look at the User Guide at http://live.gnome.org/DVBDaemon/UserGuide . EPG, scheduled recording, and the Totem plugin (for live viewing, or viewing recordings) should work fine. Basically run gnome-dvb-setup to scan for channels, then run gnome-dvb-control, go to Preferences dialog to set up “groups” (using the channel file saved in gnome-dvb-setup), and that’s it.

Some quirks I noticed so far:

  • when using the plugin for first time after starting Totem, it will try to install a decoder for “private/teletext” but doesn’t find a matching package – that doesn’t seem to do any harm, though.
  • viewing live video in Totem using the plugin often fails with error message “Could not read from resource.” (and if you run totem on console, you can also see a “503 (Service Unavailable)” error message). No idea what causes this.
  • EPG data in gnome-dvb-control is not available for all channels. Maybe it needs some more time to collect data, or maybe DVB signal is too weak. Unfortunately the GUI doesn’t indicate in the station list for which stations it has EPG data available.

Wifi on EeePC 701 with Ubuntu Hardy

December 3, 2008

Last week I noticed that wireless LAN on my EeePC 701 was quite unreliable under Ubuntu Hardy 8.04 (dropped packets, and very low bandwidth). I was using the new open-source ath5k driver, which apparently has some bugs yet. There seem to be many possible solutions floating around on the net, but what has helped for me is the madwifi driver from Tim Gardners PPA:

  • in Software Sources dialog, add deb http://ppa.launchpad.net/timg-tpi/ubuntu hardy main as package source
  • install “madwifi-kernel-source” package (this also installs dkms and some other stuff, and builds a new ath_pci kernel module); currently, the package is at version 0.3862-1
  • edit /etc/modprobe.d/blacklist: add blacklist ath5k to disable the existing ath5k driver; make sure there is no blacklist ath_pci entry in that file
  • edit /etc/modprobe.d/options to set the correct country code (otherwise you might see a line like this in dmesg: “MadWifi: ath_getchannels: Unable to collect channel list from HAL; regdomain likely 96 country code 0”): add options ath_pci xchanmode=0 outdoor=1 countrycode=276
  • after a reboot, wifi should work, and lsmod | grep ath should show that ath_pci is loaded.

Details for the PPA can be found at https://launchpad.net/~timg-tpi/+archive . The countrycode options are taken from http://wiki.voyage.hk/dokuwiki/doku.php?id=how_to_set_country_code_for_madwifi_device .

So… VNC and Youtube work fine now, so I’m quite happy. Note that this driver is not completely open source, but it should fix wifi until ath5k gets more reliable. Thanks to the madwifi hackers for this driver, and to Tim Gardner for the packaging!

Update: looks like a kernel update overwrote the madwifi driver (which I only noticed out of the blue after doing a reboot instead of suspending). So system loads old ath_pci driver -> chip is not detected -> no Wifi -> stone age :-(

DKMS documentation is scarce on the net; “dkms status” says the module is “built”. Manually running “dkms install -m madwifi -v 0.3862” only gives “Good news! Module version for wlan_xauth.ko exactly matches what is already found in kernel 2.6.24-23-generic. DKMS will not replace this module. You may override by specifying –force.”. Indeed, running “dkms install -m madwifi -v 0.3862 –force” then installs the correct ath_pci.ko in the correct place, but still… Sigh.