Comment 28 for bug 943263

Seeing this here on an Acer Aspire am3470g-uw10p with Radeon HD 6530D. The vga output dies as soon as radeon with KMS is loaded. In process of acquiring HDMI cable to test with HDMI output.

I have tried with 3.3.1 and 3.3.2 and same problem. Using xorg 1.12.1, xf86-video-ati 6.14.4, ati-dri/mesa 8.0.2 on brand new Arch Linux. Also tried Ubuntu 11.10 Live CD and same results.

Adding vga=775 radeon.modeset=0 to kernel boot line gives me a usable console interface and Xorg will actually start that way, but Xorg display is highly corrupted with bands of bright green and red lines.

Ubuntu 12.04 beta 2 gives same result except that it can successfully start a non-corrupted (but incorrect resolution) Xorg server with the kernel boot line above.

I have an identical snippet in my dmesg as the one posted by Mandeep Baines above.

This bug is marked fixed for Ubuntu in Launchpad ( https://bugs.launchpad.net/ubuntu/+source/linux/+bug/825777 ) but it doesn't work with a fully up-to-date Arch Linux. I haven't had occasion to try the specific Ubuntu kernel build (3.0.0-17.30) cited as resolving the problem (and it seems to be based on one positive result) and I don't seem to see a patch that would be applicable to a mainline kernel.

lspci:
VGA compatible controller: Advanced Micro Devices [AMD] nee ATI BeaverCreek [Radeon HD 6530D]