Alphacool LCD support in serdisplib, lcd4linux - the hard way

The Alphacool LCD is nice: 320x200 pixels, graphical, brushed aluminium with a blue back-light. I've got one in my main PC, and it's been sitting there - inactive - since I upgraded from Ubuntu Feisty. Yesterday I (finally) got it going again, with only a little mucking about.

The display is now officially in serdisplib, provided you've got libusb (and specify it in the configure), and there is a serdisplib-based driver in lcd4linux ... although it's not compiled in the standard lcd4linux package that comes with Ubuntu Intrepid.

So, first thing was to download serdisplib and compile it. To do this in a slightly-more sensible way I use checkinstall to create a .deb package. It's a good idea, because it means the software is controlled by the packaging system (and can therefore be removed or reinstalled as necessary). Install checkinstall if you don't have it

sudo apt-get install checkinstall

So, I gunzipped the serdisplib package then opened a terminal and navigated to the appropriate directory:

cd ~/serdisplib-1.97.8

This is the source-code of serdisplib, so I need to configure and make it to compile it for my system. Make sure you scroll back up and check the output of the configure, because the first time I tried it didn't compile libusb because I didn't have the libusb-dev package. This was resolved by installing it in the usual way:

sudo apt-get install libusb libusb-dev

So then, configure and make:

./configure --enable-libusb
make

Alright, at this point I had compiled the binaries, but they're still sitting in this directory (rather than the /usr/bin and other system directories). It's a good time to test out the display:

testserdisp -n alphacool -p 'USB:060C/04EB'

It's a bit weird, but the display shows up as an "EEH Datalink GmbH". Try:

lsusb

... and you can see an entry like

Bus 004 Device 002: ID 060c:04eb EEH Datalink GmbH

Anyway, my test worked - the LCD was activated and displayed a test pattern. You can run a few tests with this one, but I was just happy to see it running again. Time to install serdisplib to the system!

Normally, this is done by running something like "sudo make install", which copies the compiled files and libraries to the appropriate locations, but as I said earlier this would mean serdisplib was entirely outside the packaging system. Instead, run:

checkinstall

This will ask a couple of questions (a description) and then create a .deb package which can be installed (and removed) like any other package. Find the .deb in the same directory and either double-click it in the file manager or install it from the terminal with

sudo dpkg -i serdisplib_1.97.8-1_i386.deb

What I didn't realise, but probably should have, is that this installs to /usr/local (e.g. /usr/local/bin, /usr/local/lib) rather than /usr. This isn't really a problem, but lcd4linux had trouble a little further on finding the libraries in /usr/local/lib rather than /usr/lib. At the time, I just copied the serdisplib stuff from /usr/local/lib to /usr/lib, but it would probably be better to either configure serdisplib to use /usr, or configure lcd4linux to look in /usr/local/lib. Oh well.

So, onto lcd4linux. I already had lcd4linux installed from the Ubuntu repositories, but it didn't include the serdisplib driver. You can check what drivers are included with

lcd4linux -l

So it was time to download the source code for lcd4linux too. Gunzip this in the same way as serdisplib. After attempting to compile this a couple of times I found I needed to patch the source code. Download the patch to your home directory and apply it

cd ~
patch -p0 < lcd4linux-0.10.1_rc2-nordtsc.patch

then we can compile and install it

cd lcd4linux-0.10.1-RC2
./configure
make
checkinstall
sudo dpkg -i lcd4linux-0.10.1_RC2-1_i386.deb

Cool! So now I had the new lcd4linux AND it had serdisplib support. Because I had the Ubuntu repository one too, I could test the two:

/usr/sbin/lcd4linux -l

That's the Ubuntu repo one

/usr/local/bin/lcd4linux -l

and that's the new one. Importantly, this has the line

serdisplib          : any

showing that it has the serdisplib support compiled in.

Because I had installed the repo one first, I already had an init.d script for starting lcd4linux at boot time. However, you want to edit /etc/init.d/lcd4linux and specify the absolute path to the new lcd4linux executable. i.e. change the DAEMON line to:

DAEMON=/usr/local/bin/lcd4linux

Also, you need an lcd4linux config file in /etc/lcd4linux.conf. The easiest way to get this is copy the sample one

sudo cp /usr/share/doc/lcd4linux/lcd4linux.conf.sample.gz /etc/
cd /etc
sudo gunzip lcd4linux.conf.sample.gz
sudo mv lcd4linux.conf.sample lcd4linux.conf

Now edit /etc/lcd4linux.conf with your favourite text editor. Find the SerDispLib display section and replace it with this:

Display SerDispLib {
   Driver 'serdisplib'
   Port 'USB:060C/04EB'
   Model 'ALPHACOOL'
}

Then go to the end of the file and comment/uncomment the appropriate line to specify the SerDispLib display

Display 'SerDispLib'
#Display 'LCD-Linux'
#Display 'LCD2041'
#Display 'LK202'
#Display 'LK204'
#Display 'MI240'
#Display 'CW12232'
#Display 'HD44780-generic'
#Display 'HD44780-WinAmp'

... and a layout

Layout 'Default'
#Layout 'TestLayer'
#Layout 'TestImage'
#Layout 'L8x2'

All being well, you should be able to start up lcd4linux and have the display activate with

sudo /etc/init.d/lcd4linux start

Cool!

There's a lot of tweaking and playing that you can do with lcd4linux layouts, so go nuts.

Mount an ISO as a DVD drive

To mount an ISO image, use the loopback device:

sudo mount -o loop somedvd.iso /media/fakedvd

Now you can point any DVD programs at /media/fakedvd rather than /dev/dvd, for example.

Password-less logins with PAM

Sometimes you want certain to be able to log in to certain user accounts without a password -- for a guest account, for example. It's not terribly secure, sure, but sometimes you don't need that security. Read on for how to do this on any GNU/Linux OS that uses PAM and GDM.

To enable password-less logins for any operating system that uses PAM and GDM, edit /etc/pam.d/gdm to add the following line:

   auth    sufficient      pam_listfile.so sense=allow file=/etc/passwordless item=user
   
   @include common-auth
   ... 

Then create the /etc/passwordless file (readable only by root). List each user you want to login without a password, one per line.

If you are using the GDM autologin feature, add the line "@include common-pamkeyring" to /etc/pam.d/gdm-autologin. I haven't tried it, but this is reported to allow the no-password user wireless access without entering the keyring password.

If not, you need a script like the following to your session startup:

   #!/bin/sh
   exec echo -n "MyKeyringPassword" | /usr/lib/libpam-keyring/pam-keyring-tool -u -s

However, pam-keyring-tool is not included in Ubuntu 7.10, so you need to compile it.