I'm using the xf86-video-ati-6.9.0 driver(not fglrx ones;) and it work fine at least in the 2.6.27-rc* kernel. Under the 2.6.27-git9 kernel, if I enable the DRI in xorg.conf, it will give me totally black screen. Even Ctrl+Alt+F1 doesn't work. It seems that the screen was totally turned off. I will provide dmesg and X.0.log soon.
Created attachment 18391 [details] dmesg
Created attachment 18392 [details] X.0.log that works(i.e, DRI disabled) This is the X log when DRI is disabled. Could someone tell me how to dump X log in a totally black screen? ;) I wish the dmesg and this X log could do some help.
You should be able to see previous X logs in /var/log/Xorg.0.log.old or something like that.
Created attachment 18396 [details] X log when dri enabled
This problem can be fixed by simply revert: commit edc6f389f6ae9cb7621270a8ddbb1892bd8df125 "radeon: fix PCI bus mastering support enables." As Alex is the author of the commit, I add CC to you. Would you please see what is going on here?
there was an error in the logic. should be be fixed by these commits: http://cgit.freedesktop.org/mesa/drm/commit/?id=848f00d77381d8b442c096476302796f8fe122fa http://cgit.freedesktop.org/mesa/drm/commit/?id=e1372f67274baa44419e000f5d3d6b2e81be2b51
What exactly do they apply to?
they are against the upstream drm git tree, but should apply pretty trivially to the kernel as well.
I think the problem get fixed by the commit: 4e270e9b8a9d246290f3901f1fb6c5efdb734ddf drm/radeon: fixup further bus mastering confusion. at least it works well on my box ;) So I will close this entry. Thanks Alex Deucher.