Fabio, I think the right parameter is "radeon.modeset=0" (and not "radeon.nomodeset=0") as reported in https://wiki.ubuntu.com/X/KernelModeSetting . ADR, which parameter have you try?
Fabio, I think the right parameter is "radeon.modeset=0" (and not "radeon. nomodeset= 0") as reported in https:/ /wiki.ubuntu. com/X/KernelMod eSetting . ADR, which parameter have you try?