I just upgraded to Ubunto 13.04 with kernel 3.8.0-19, and this problem seems to have returned.
Modifiying the line in Grub to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=" , as suggested in comment #36 does not help. Instead, the OS boots into an unlit screen.
I just upgraded to Ubunto 13.04 with kernel 3.8.0-19, and this problem seems to have returned. LINUX_DEFAULT= "quiet splash acpi_osi=" , as suggested in comment #36 does not help. Instead, the OS boots into an unlit screen.
Modifiying the line in Grub to GRUB_CMDLINE_