Created attachment 114484 [details]
Warzone

The problem is viewable in my attached picture. It's the game Teeworlds for example - with corrupt font.

Mint 17 Mate 64 is same as in Mint 17 Xfce 64. Problems with that notebook-graphic also on Ubuntu (and when I remember correct Debian, too)

HalfLife and Warzone 2100 looks same.

Distros were all fresh installed. (in Ubuntu/Unity the top taskbar has the same 'striped and defect'look directly at first startup after install)

Some more informations, now Mate 17.1:

dmesg | grep -i radeon

[ 3.414242] [drm] radeon kernel modesetting enabled.
[ 3.414339] fb: switching to radeondrmfb from EFI VGA
[ 3.415143] radeon 0000:01:05.0: VRAM: 256M 0x0000000070000000 - 0x000000007FFFFFFF (256M used)
[ 3.415146] radeon 0000:01:05.0: GTT: 512M 0x0000000080000000 - 0x000000009FFFFFFF
[ 3.415274] [drm] radeon: 256M of VRAM memory ready
[ 3.415276] [drm] radeon: 512M of GTT memory ready.
[ 3.424768] [drm] radeon: 1 quad pipes, 1 z pipes initialized.
[ 3.426141] radeon 0000:01:05.0: WB enabled
[ 3.426146] radeon 0000:01:05.0: fence driver on ring 0 use gpu addr 0x0000000080000000 and cpu addr 0xffff880035a38000
[ 3.426166] [drm] radeon: irq initialized.
[ 3.426387] [drm] radeon: ring at 0x0000000080001000
[ 3.428091] [drm] radeon atom DIG backlight initialized
[ 3.428096] [drm] Radeon Display Connectors
[ 4.040201] fbcon: radeondrmfb (fb0) is primary device
[ 4.040282] radeon 0000:01:05.0: fb0: radeondrmfb frame buffer device
[ 4.040285] radeon 0000:01:05.0: registered panic notifier
[ 4.044113] [drm] Initialized radeon 2.39.0 20080528 for 0000:01:05.0 on minor 0
------------------------------------------------------------

glxinfo | grep gl

server glx vendor string: SGI
server glx version string: 1.4
server glx extensions:
client glx vendor string: Mesa Project and SGI
client glx version string: 1.4
client glx extensions:
    GL_ARB_texture_non_power_of_two, GL_ARB_texture_rectangle,
    GL_EXT_texture_object, GL_EXT_texture_rectangle, GL_EXT_texture_sRGB,
    GL_NV_texture_env_combine4, GL_NV_texture_rectangle, GL_NV_vdpau_interop,
------------------------------------------------------------
I changed nomodeset at startup with shift, e - but it resulted
in complete garbage - the splash-screen where I normally enter my password
was completely defect, b/w and absolutely unusable.

I furthermore created xorg.conf, edited it with nano at the right place and changed the line with 'Option "EXAPixmaps"' to "off", afther that it started nomal - but thats all, its also unusable. Screen corrupts in a way I've never seen before, parts were rotated completely, looked crazy. But that was not what I looked for.
------------------------------------------------------------

Any ideas? It is impossible to play games :( Thanks for any help!

More, maybe useful, don´t know, with 1 or two more pics, too:
https://bugs.freedesktop.org/show_bug.cgi?id=35457