sadevil.org

Since I have a rather well-scaled desktop PC (nothing really fancy by today’s specs, but it’s underused as it is), and my gf sometimes wants to use it, and sometimes we both want to use it at the same time, I decided to turn it into a multiseat configuration.

What’s a multiseat? Basically you connect a second set of input peripherals (keyboard, mouse) and a second screen (and if necessary a second video card) and reconfigure it to act as a separate pc.
And with Linux, you just can, without a lot of trouble.

There are some different multiseat setups: those that run separate X servers (one per display), and those that run one X server for all displays and then run a nested server on top of that to split out the actual displays. The ‘problem’ wit the latter is that you usually don’t have any 3D acceleration left, though if you use Xephyr these days that seems to work aswell.

I opted for the first option.

My hardware (that matters for this setup):

• Mice: 2 simple Logitech usb mice
• Keyboards: 2 usb keyboards (one Cherry Cymotion Linux Master & one labtec Ultraflat)
• Graphics: an onboard ATI Radeon HD 3200 (this is part of the AMD 780 chipset) video chip on my Asrock motherboard (was originally disabled and enabled for this multiseat setup) and an addon ATI Radeon HD 4850 card (with an RV700 chip).
• Screens: two screens – in this case, one 20.1″ Viewsonic VX2025wm and one 22″ (newly purchased) LG w2253TW

Notes:

1. It is advised to use chips that can be driven with the same driver for a multiseat setup!
2. If you use an onboard chipset (like I do), you’ll need to change the boot order so that this chip is actually used as the primary device, otherwise it won’t be initialised correctly.

Originally I had the ATI binary driver fglrx installed, but this does _not_ play well with a multiseat setup. The initialisation of the second card causes the system to hardlock.
Since this driver doesn’t work, I went for the xf86-video-ati driver, which is completely opensource, and in combination with a recent kernel allows for kernel mode setting. You do need the firmware for the card, usually found in the firmware-linux packages of your favourite distribution.

So, the works:

Requirements

1. Get a spankingly fresh kernel. 2.6.33 at least, preferably newer. Compile it with KMS support enabled. Note that when you enable KMS support, you’ll lose your console unless you compile in fbcon, but I advise against this, as this doesn’t seem to play well with a multiseat setup.
2. Install the linux-firmware package or get the necessary firmwares for your cards (to get 3D acceleration)
3. Get a decently fresh Mesa (7.7 branch)
4. Lastly, get a mjummy fresh xf86-video-ati driver.

Originally, I compiled all these and installed them over the existing binaries in /usr, but fortunately my favourite distribution Debian has the necessary components in Sid and Experimental. these days.

Xorg.conf changes

After everything is installed, you need to modify your xorg.conf file.

ServerFlags

Section "ServerFlags"
        Option      "DefaultServerLayout" "seat0"
        Option      "AllowMouseOpenFail"  "true"
        Option      "AutoAddDevices" "false"
EndSection

The AutoAddDevices line is important, otherwise we can’t map the devices to the right seat.

The actual graphic chips/cards:

Section "Device"
        Identifier  "ATI RadeonHD 4850"
        Driver      "ati"
        BusID       "PCI:2:0:0"
        Option      "Int10" "off"
EndSection

Section "Device"
        Identifier   "ATI RadeonHD 3200"
        driver       "ati"
        BusID        "PCI:1:5:0"
        Option       "Int10" "off"
EndSection

Int10 off is important here, otherwise the second card will fail to initialise.
Do not forget to change the PCI identifiers! They probably won’t match my setup. You can find them by using lspci, for instance on my setup:

lspci | grep  "Radeon HD"
01:05.0 VGA compatible controller: ATI Technologies Inc Radeon HD 3200 Graphics
02:00.0 VGA compatible controller: ATI Technologies Inc RV770 [Radeon HD 4850]

So you can see that the HD3200 is on address 1:5 and the HD4580 is on address 2:0.

The monitors (nothing fancy)

Section "Monitor"
        Identifier   "Viewsonic Vx2025wm"
        Option      "DPMS"
EndSection

Section "Monitor"
        Identifier    "LG W2253TW"
        Option       "DPMS"
EndSection

Screen section (mapping monitors and cards)

Section "Screen"
        Identifier        "Screen0"
        Device           "ATI RadeonHD 4850"
        DefaultDepth   24
EndSection

Section "Screen"
        Identifier        "Screen1"
        Device           "ATI RadeonHD 3200"
        DefaultDepth   24
EndSection

Next, the ServerLayout sections, one per seat:

Section "ServerLayout"
        Identifier     "seat0"
        Screen      0  "Screen0" 0 0
        InputDevice    "Mouse0" "CorePointer"
        InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "ServerLayout"
        Identifier     "seat1"
        Screen      1  "Screen1" 0 0
        InputDevice    "Mouse1" "CorePointer"
        InputDevice    "Keyboard1" "CoreKeyboard"
EndSection

Next, the input devices:

Section "InputDevice"
    Identifier     "Keyboard0"
    Driver         "evdev"
    Option         "Device" "/dev/input/by-path/pci-0000:00:12.1-usb-0:3:1.0-event-kbd"
    Option         "XkbModel" "pc105"
    Option         "XkbLayout" "us"
    Option         "XkbRules"   "xorg"
EndSection

Section "InputDevice"
    Identifier     "Mouse0"
    Driver         "evdev"
    Option         "Protocol" "ExplorerPS/2"
    Option         "Device" "/dev/input/by-path/pci-0000:00:13.0-usb-0:3:1.0-event-mouse"
EndSection

Section "InputDevice"
    Identifier     "Keyboard1"
    Driver         "evdev"
    Option         "Device" "/dev/input/by-path/pci-0000:00:12.2-usb-0:3.1:1.0-event-kbd"
    Option         "XkbModel" "pc105"
    Option         "XkbLayout" "us"
    Option         "XkbRules"   "xorg"
EndSection

Section "InputDevice"
    Identifier     "Mouse1"
    Driver         "evdev"
    Option         "Protocol" "ExplorerPS/2"
    Option         "Device" "/dev/input/by-path/pci-0000:00:12.2-usb-0:3.2:1.0-event-mouse"
EndSection

You need to change the device paths to match the devices you want, either by checking /dev/input/by-path/ or by /dev/input/by-id/. The benefit of using by-id is that if you replug your devices, they’ll still be mapped correctly. Since I have devices with the same ID, this didn’t work for me.

All these changes sofar should allow you to manually start up the X servers with the respective keyboard/mouse/screen settings. You should be able to test it with these commands:

/usr/bin/X -br -nolisten tcp -layout seat0 -sharevts \
      -novtswitch -isolateDevice PCI:2:0:0

or

/usr/bin/X -br -nolisten tcp -layout seat1 -sharevts \
      -novtswitch -isolateDevice PCI:1:5:0

KDM changes

Now, since I want both the X servers to be available at boot time, and I’m using KDE anyway, I went with KDM.

In the [General] section, look for a line reading:

StaticServers=:0

change it to:

StaticServers=:0,:1

Also, change:

ReserveServers=:1,:2,:3

to:

ReserveServers=:2,:3

Next, look for the [X-:0-Core] section, and copy the entire block, creating a second block with the section name [X-:1-Core].

In the [X-:0-Core] section, look for the line

ServerArgsLocal=-br -nolisten tcp

and change it to

ServerArgsLocal=-br -nolisten tcp -layout seat0 -sharevts -novtswitch -isolateDevice PCI:2:0:0

In the [X-:1-Core] section, look for the line

ServerArgsLocal=-br -nolisten tcp

and change it to

ServerArgsLocal=-br -nolisten tcp -layout seat1 -sharevts -novtswitch -isolateDevice PCI:1:5:0

One KDM restart later (/etc/init.d/kdm restart) you should have two X servers running, both on their respective screens!

Last but not least, kudos to WKPG wiki for the helpful article ;)

I wanted to test some crap in VMWare, didn’t feel like messing with the entire server thing so went for the player. Unfortunately, this thing doesn’t work against the 2.6.32 kernel.

After installation, you can fix it with as follows (as root):


cd /tmp
tar xf /usr/lib/vmware/modules/source/vmnet.tar
tar xf /usr/lib/vmware/modules/source/vmci.tar

cd vmnet-only
sed -i "/vnetInt.h/ a\#include \"compat_sched.h\"" vnetUserListener.c

cd ../vmci-only/include
sed -i "/compat_page.h/ a\#include \"compat_sched.h\"" pgtbl.h

cd /tmp
tar cf /usr/lib/vmware/modules/source/vmnet.tar vmnet-only
tar cf /usr/lib/vmware/modules/source/vmci.tar vmci-only


and rerun vmplayer.

I recently purchased an Alcatel Onetouch X200 3G USB modem, to be able to use internet on various locations where there is no wired or wifi available. Works fine under Windows/Mac OS X, bit more of a hassle under Linux.

Here are some hints on how to get it to work:

• You need to install usb-modeswitch to switch the card from it’s builtin usb-storage mode to the USBModem mode. Configuration is done in /etc/usb_modeswitch.conf
• Use /dev/ttyUSB2. The other two ports that your modem will give don’t really work well.
• Also, use atleast kernel 2.6.31. Earlier ones might not work.
• Disable PIN authentication on your SIMcard! This one thing was what kept it from working decently – I tried tons of things, and when I disabled the PIN, it worked nearly instantaneously.
  The command to do PIN auth is AT+CPIN=1111 (changing 1111 by your actual PIN), but when issuing this command the modem accepts it, but very often freaks out afterwards. Weird.
  You can find a nice list of GSM modem AT codes on gsm-modem.de.

Thats about it!

Since I’m a lazy git, I want my laptop to automatically switch back & forth between my wired and wireless interfaces. Seems that stuff like Network Manager can do that for you, but it’s not really my thing. I don’t like stuff where you need a GUI to configure it, a duplicaton of network configuration, and it also tends to hang my machine. No idea why, though.

After an afternoon of fiddling around with several things, I came up with the recipe:
1 portion ifplugd, a good mix of ifupdown configuration with guessnet mappings, and some home-grown scripts. Mix well, and let simmer over a hot stove for half an hour. ;)

The details (tailored to Debian Sid):

1. Install ifplugd and guessnet: apt-get install ifplugd guessnet
2. Configure the interface you want ifplugd to monitor. For me, this is eth0 (wired ethernet). You can do this by editing /etc/default/ifplugd and adding eth0 in the INTERFACES field.
   Restart ifplugd (/etc/init.d/ifplugd restart)
3. Edit your /etc/network/interfaces file the way you like it. I’m using multiple wireless entries with guessnet:
   

   mapping ath0
           script guessnet-ifupdown
           map verbose: false
           map debug: false
           map autofilter: true
   
   iface ath0-work inet dhcp
           test wireless essid WORK
           wpa-ssid WORK
           wpa-key-mgmt WPA-PSK
           wpa-proto WPA
           wpa-psk "***"
           wpa-driver wext
   
   iface ath0-home inet dhcp
           test wireless essid HOME
           wpa-ssid HOME
           wpa-key-mgmt WPA-PSK
           wpa-proto WPA
           wpa-psk "***"
           wpa-driver wext
   

   For syntax info, see man guessnet

4. Replace the script in /etc/ifplugd/action.d with something more usable. The installed script only calls ifup or ifdown depending on what’s happening. What we want is to ifdown the interface, and ifup the other.

   Something like this:

   #!/bin/sh
   set -e
   
   WIRED_INTERFACE="eth0"
   WIFI_INTERFACE="ath0"
   WIFI_MODULE="ath_pci"
   IFUPDOWN_STATE="/etc/network/run/ifstate"
   
   if [ $# -ne 2 ]; then
           echo "Incorrect usage!"
           echo "$0:  "
           exit 1
   fi
   
   case "$2" in
   up)
           if [ "$1" = $WIRED_INTERFACE ]; then
                   # Wired interface is going up, bring wireless down
                   # if it is active.
                   WIFI_MODULE_LOADED=$(lsmod | grep ^$WIFI_MODULE | wc -l)
                   if [ $WIFI_MODULE_LOADED -eq 1 ]; then
                           /sbin/ifdown $WIFI_INTERFACE
                           /sbin/rmmod $WIFI_MODULE
                   fi
                   /sbin/ifup $WIRED_INTERFACE
           else
                   /sbin/ifup $1
           fi
           ;;
   down)
           if [ "$1" = $WIRED_INTERFACE ]; then
                   # Wired interface is going down, bring up the
                   # wireless one.
                   /sbin/ifdown $WIRED_INTERFACE
   
                   /sbin/modprobe $WIFI_MODULE
                   /sbin/ifconfig $WIFI_INTERFACE up
                   sleep 5
                   /sbin/ifup $WIFI_INTERFACE
   
                   WIFI_CONFIGURED=$(grep ^$WIFI_INTERFACE $IFUPDOWN_STATE | wc -l)
                   if [ $WIFI_CONFIGURED -eq 0 ]; then
                           # Interface was not configured, bring it back down
                           # to save power
                           /sbin/rmmod $WIFI_MODULE
                   fi
           else
                   /sbin/ifdown $1
           fi
           ;;
   esac
   

Now, every time ifplugd configures up eth0, ath0 is automatically deconfigured, and vice versa.
The actual configuration of the interfaces is still in /etc/network/interfaces, so you can still handle it by hand if you want to.

As always, it works fine for me, but YMMV, and TIMTOWTDI!

I just finished updating my machine to the latest Linux kernel, 2.6.28. All worked, except for VMWare Server (which was still at 1.0.8). Since 2.0 has been released, time for an upgrade!

Downloaded, installed, configuration didn’t work for the vsock module. Actually, it built, but failed to load due to some missing symbols. After some digging I came across the following patch that modifies the vmware-config.pl script:

(note: very bad wordwrapping here, download the file below and use that!)


--- /usr/bin/vmware-config.pl.orig 2008-11-28 12:06:35.641054086 +0100
+++ /usr/bin/vmware-config.pl 2008-11-28 12:30:38.593304082 +0100
@@ -4121,6 +4121,11 @@
return 'no';
}

+ if ($name eq 'vsock') {
+ print wrap("VMWare config patch VSOCK!\n");
+ system(shell_string($gHelper{'mv'}) . ' -vi ' . shell_string($build_dir . '/../Module.symvers') . ' ' . shell_string($build_dir . '/vsock-only/' ));
+ }
+
print wrap('Building the ' . $name . ' module.' . "\n\n", 0);
if (system(shell_string($gHelper{'make'}) . ' -C '
. shell_string($build_dir . '/' . $name . '-only')
@@ -4143,6 +4148,10 @@
if (try_module($name, $build_dir . '/' . $name . '.o', 0, 1)) {
print wrap('The ' . $name . ' module loads perfectly into the running kernel.'
. "\n\n", 0);
+ if ($name eq 'vmci') {
+ print wrap("VMWare config patch VMCI!\n");
+ system(shell_string($gHelper{'cp'}) . ' -vi ' . shell_string($build_dir.'/vmci-only/Module.symvers') . ' ' . shell_string($build_dir . '/../'));
+ }
remove_tmp_dir($build_dir);
return 'yes';
}


To use it, download vmware-configplpatch.txt, and run
cat vmware-configplpatch.txt | patch -p0, and rerun the VMWare configuration script.

Thanks to this post on the Ubuntu Forums for the solution!

At work we regularly have to send over files to $vendor. $Vendor has two ways of accepting files: FTP, and Webdav (over https). Since our company’s policy is to not send things out unencrypted, we have to go the webdav way. It’s also the policy to send things over our internetproxy if possible.

After some searching for a console-based webdav client we ran across cadaver, a lightweight client that seemed to do the trick. It has proxy support, so great ;)

What isn’t so great is that it doesn’t have any way to supply the proxy authentication in a non-interactive way, which is crucial to allow us to script this file transfer.

Today I took the time to create a patch that allows just that – setting the proxy info in advance. It also includes a parameter to trust the server certificate implicitly, otherwise it was yet another step where cadaver would come and ask for user input.

Now it works like a charm! :)

Sade linked me to this nice ebook by Neil Gaiman, Neverwhere. Unfortunately, you need Adobe Digital Editions for it, which only exists for Windows and Mac. Since she’s a Linux user, that one didn’t really fly with her.

So, to get that thing to work, here’s a very low-tech way of doing it:

1. Install Digital Editions on a supported OS (I used Mac OS)
2. Download/open the ebook’s ebx.etd file
3. Let Digital Editions open, download and authenticate the file
4. Print to PDF 40 pages (the damn thing won’t let you print more)
5. Close the digital Editions app
6. Delete (in my case) the ~/Documents/Digital Editions directory
8. Reload the webpage
9. Goto step 2

Repeating this until you have the entire ebook in PDF’s for easy reading at home, under your favourite OS / device! ;)

Here’s a short how-to to get the iodine dns tunnel working on your Mac.

In this short howto, I’ll assume you’ll be using a linux server to act as your gateway to the world. I’ll also assume you’ve read the iodine documentation and setup your DNS accordingly. For my example, I’ll be using a (nonexistant) DynDNS.org static DNS entry, iodine.rulestheworld.tld. I’ll also assume that you’ll be using a public internet address of 1.2.3.4, and a private subnet of 10.0.0.1.

1. Install the tun/tap driver for Mac OS X. Easy as doing *click* *click* done! :p
2. Next, install iodine on your Mac. Easy as download, extract, and typing make; make install
3. Now, install iodine on your linux box. It’s included in the package repositories of the usual suspects, for instance debian: apt-get install iodine.

   Start it (or configure it to use) with:
   iodined -P <password> <unused private IP> <dns name>
   or in our example:
   iodined -P mypass 10.0.0.1 iodine.rulestheworld.tld

   This should return the following:

   Opened dns0
   Setting IP of dns0 to 10.0.0.1
   Setting MTU of dns0 to 1024
   Opened UDP socket
   Listening to dns for domain iodine.rulestheworld.tld

4. Configure your linux box for IP forwarding: sysctl -e net.ipv4.ip_forward=1
(and add this to your /etc/sysctl.conf file), and configuring your firewall (iptables) for masquerading:
   iptables -t nat -A POSTROUTING -s 10.0.0.0/255.255.255.0 -o eth0 -j MASQUERADE
5. Next, download NStun.sh, a very handy script that does all the hard work of changing the routes and so on :p

   You’ll want to change the script: change the first lines as the script reads, and lower, change the
   

   NS=`grep nameserver /etc/resolv.conf|head -1|awk ‘{print $2}’`

   line to read

   NS=”62.213.207.197″

Now, start NStun.sh on your Mac, and surf away! (well, slowly, but freely, atleast!)

I was trying to get xrdp running on my Linux box, so I could takeover the screen from the outside world. The rdp protocol is a (huge) bit more performant than VNC, which is why I wanted to use it.

Today I was trying for the 3rd time to get it to work, using CoRD as an RDP client, but I never got any image back – the client started, I saw the connection being built up, but I never got any image over. Starting rdesktop locally gave me the output I expected.

This gave me the idea of using Microsoft Remote Desktop Connection Client for Mac 2 Public Beta, to see if it might be a problem with the client… and yup, it is.

Seems CoRD 0.4.3 (the current stable) is unable to handle the output of xrdp. I now installed the 0.5 beta 1 which works without any problems.