I can sort-of help you with this one. You need to find out what
graphics unit/chip/whatever is on the MoBo.

Somewhere on your system's case (underside for laptops, side panel
for desktops, and often revealed in the BIOS setup) is an identifier
known as a "Service Tag" (sometimes abbreviated "SvcTag"). It'll be
typically 6 to 8 alphanumerics.

Visit www.dell.com, click on "Support" (upper right corner).
On that page, click on "I'm looking for drivers and downloads".
On that page, find "Choose by service tag" and click "Enter a tag".
On that page, enter the service tag and click "Go".

You'll now be on a page specific for your system, and there are lots
of options including Warranty, Manuals, drivers, etc. One of the
options is a copy of the shipping/packing slip as originally sent
with the system which identifies all the hardware, devices, etc. on
the system. Heh, the service tag for one of my systems I entered to
get to that page shows "Operating System: Red Hat Linux 7.0" though
it's presently running SLED-10-SP1 (Suse Linux Enterprise Desktop).

A Google search on the device(s) should point you to where you may
find the Linux drivers. Also do this: on the "Operating System"
display box, click the pull-down menu button and see what Operating
Systems are available, Linux may be there! When I just did this for
my system, the choices are Red Hat Linux 7.0/6.2,6.1, Windows 2000,
Linux, various Windows releases, AIX, UnixWare, Solaris, Open Server,
HPUX, and OS/2. Selecting one of those changes the list of available
drivers so you just may luck out.