Graphics artifacts on Slackware 14.0, Radeon HD 6750
I got a system with i5 and Radeon HD 6750 video card.
On Slackware 13.37 I just couldn't run X because it didn't recognize the chipset properly and had to use vesa driver. But that is history.
I just installed Slackware 14.0, full, plain install.
Immediately after booting, after it loads the framebuffer kernel driver (radeon, drm, kms), small red horizontal lines appear at random and change with display contents.
I configured X with xorgsetup (plain autodetect everything) and I started X.
Here there are a lot more such artifacts, some red, some different colors. They multiply so the screen becomes visually unusable after a short time.
From X.log :
(II) Kernel mode setting enabled
(WW) falling back to old probe method for modesetting
(WW) falling back to old probe method for vesa
(--) Radeon chipset "TURKS" ChipID=0x6759
Using Driver "vesa" in the config file yields no such artifacts.
In text console, with framebuffer loaded, there are artifacts, but much fewer.
How can I solve this and use the native driver for video?