https://bugs.freedesktop.org/show_bug.cgi?id=66963
--- Comment #170 from Thierry Vignaud thierry.vignaud@gmail.com --- I don't know if it can helps you (Alex), but as of kernel-3.12.6/mesa-10.0.1, my RV670 ([Radeon HD 3690/3850]) is pretty reliable when booting wit dpm (usually for resuming hibernation): - it consistently fails on the first electric power on (the screen blacked out, "no signal") - it consistently works smoothly after powering off then powering on after a couple seconds: it resumes smoothly
Does it helps you figure what can be wrong?