Problems with Radeon video card in Debian Jessie testing
 

I tried LMDE mint and really like the interface, but I returned to Debian because I liked the full access to the repositories that seemed lacking with Mint. However I just can't seem to get the driver right for my video card. The card worked great with Mint. I wonder if Debian actually has the latest driver for my Radeon HD 6950 card. The driver installed by Debian doesn't have the highest resolutions for the card as Mint had. I actully upgraded Debian during installation to Debian Jessie Testing snapshot taken on 12/30/2013. I should be pretty much up to date.

The HD6950 should work out of the box with the free radeon drivers and the Catalyst/fglrx drivers, though the Catalyst/fglrx in Testing may not be the newest version.
I recommend to check your Xorg.0.log for error messages.

Problems with Radeon video card in Debian Jessie testing
 

I checked the log file Xorg.O.log and did find an error, but I don' see how to fix it.
21.570] Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[ 21.570] (==) Log file: "/var/log/Xorg.0.log", Time: Fri Jan 3 06:38:24 2014
[ 21.616] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[ 21.645] (==) No Layout section. Using the first Screen section.
[ 21.645] (==) No screen section available. Using defaults.
[ 21.645] (**) |-->Screen "Default Screen Section" (0)
I see that it did load the Radeon driver module.
21.740] (II) LoadModule: "radeon"
[ 21.741] (II) Loading /usr/lib/xorg/modules/drivers/radeon_drv.so
[ 21.763] (II) Module radeon: vendor="X.Org Foundation"
[ 21.763] compiled for 1.14.3, module version = 7.2.0
[ 21.763] Module class: X.Org Video Driver
[ 21.763] ABI class: X.Org Video Driver, version 14.1

It lists a ton of Radeon drivers, and the HD 6950 is among them, and lists it as "cayman" which appears to be the GPU of the card. But unloads the drive later.
21.806] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[ 21.824] (II) Module fbdevhw: vendor="X.Org Foundation"
[ 21.824] compiled for 1.14.5, module version = 0.0.2
[ 21.824] ABI class: X.Org Video Driver, version 14.1
[ 21.824] (EE) open /dev/fb0: No such file or directory
[ 21.824] (EE) Screen 0 deleted because of no matching config section.
[ 21.824] (II) UnloadModule: "radeon"

I don't know how to fix it.

Please show us the full Xorg log file, as well as the output of 'dmesg'

Adam

Do you have the firmware package installed (firmware-linux-nonfree)?

The latest git mesa+drm+kernel+xf86-ati has wonderful support for the 6xxx series AMD cards, but Debian has some older versions in the repos.

Thanks to all who responded to my question. It was the firmware thing that grandinaruvasile pointed out. Loaded that and everything's good. Thanks again.