[Libdlo] Successfully used Lenovo USB/DVI Adapter (DL-195) at 1920x1200 with Ubuntu 9.04

[Max Reichardt]

Strangely, the D-Sub connector of my notebook failed. So I thought I'd 
give a USB-to-DVI adapter a try and got one yesterday. After 
experimenting for quite a long time, I finally made it work with Ubuntu 
9.04 and a 1920x1200 screen.

I might be stating the obvious, but I thought I'd post some hints in 
case anyone else has similar problems with high resolutions.

- Follow the steps in the Wiki 
http://libdlo.freedesktop.org/wiki/Ubuntu9.04 - but use the newer 
http://projects.unbit.it/downloads/displaylink-mod-0.3.tar.gz instead of 
udlfb in the 
http://projects.unbit.it/downloads/udlfb-0.2.3_and_xf86-video-displaylink-0.3.tar.gz 
archive.
- Before compiling displaylink, change line 84 of displaylink-main.c to
    dev->backing_buffer = vmalloc(dev->screen_size);
and line 306 of displaylink-usb.c to
    dev->screen_size = 1920 * 1200 * (FB_BPP / 8);

Generally, things run nicely and I can start applications such as 
Eclipse on the display-linked screen. Performance is reasonable and the 
picture is very clear compared to the D-Sub output.
I noticed a few issues:
- GNOME's left and right-click menus are not visible. The same is true 
for the panels at the top and bottom (I don't use Compiz; tried themes 
Cillop and Human).
- If the resolution specified in the xorg.conf does not match the 
screen's native resolution, my screen shows a bad, unstable picture with 
strange blinking artifacts.
- If no screen is connected to the USB/DVI-Converter, my system crashes.
- Patching the glib following the instructions in the Wiki 
http://libdlo.freedesktop.org/wiki/Ubuntu9.04 turned my German GNOME 
into a partly-English GNOME.

Anyway, thanks for your great work and I'm very much looking forward to 
the next release! The modified Intel driver would be particularly 
appreciated... :-)

Best Regards,
Max Reichardt