I have the same problem, and it's happening to a lot of people. See this upstream bug report. The only solution right now is to downgrade.
Maybe I'll have more luck here than in the gentoo forums. Basically, since updating to xf86-video-ati-7.0.0, if my discrete gpu is enabled, X doesn't start (segfaults). Logs:
http://pastebin.com/vm4vEW8z <- video-ati-6.14, ati GPU enabled (works ok)
http://pastebin.com/XfKAkLSs <- video-ati-7.0, ati GPU enabled (segfaults)
http://pastebin.com/YjxNwsMQ <- video-ati-7.0, ati GPU disabled (works ok)
Differences in the logs between xf86-video-ati-6.14 and xf86-video-ati-7.0:
* With 6.14 and the ati GPU enabled, Xorg seems to detect the ati card (it loads intel_drv in line 91 and ati_drv in line 96) but doesn't try to initialize the ati card (it uses the intel card, as it should, and there are no more messages about radeon/ati after line 96, just intel).
* With 7.0 and the ati GPU enabled, Xorg loads intel_drv (91), ati_drv (96) and a new (?) radeon_drv (102). Now there are several messages mentioning radeon after the intel messages (lines 150- and 471-), and then it segfaults.
* With 7.0 and the ati GPU disabled before starting X, Xorg just loads intel_drv (88). No mention of radeon anywhere and no problems afterwards.
I could disable the amd gpu in a service before xdm starts, but that's not a solution, it's an ugly workaround. I'd rather find out why 6.14 worked fine and 7.0 doesn't.
Thanks!
I have the same problem, and it's happening to a lot of people. See this upstream bug report. The only solution right now is to downgrade.