Kernel 3.14-rc8 (with PRIME) + mesa 10.2-git (radeon driver with kms and dpm)
Still the same issue, suspend + resume works fine but the laptop's screen does
not turn back on. Using an external monitor confirms that the system itself is
functional after resume. When running fglrx, there is no issue.
HP dv6z 6100 CTO QE (ca. 2011). CPU: AMD 18-3510mx, iGPU: Radeon HD 6620g,
dGPU: Radeon HD 6750m.