Comment 24 for bug 1778011

Also, something, probably prime-select, adds nouveau.runpm=0 to GRUB_CMDLINE_LINUX_DEFAULT

$ cat `which prime-select` | grep nouveau.runpm
        boot_params['nouveau.runpm'] = '0'
                                 self._grub_path, ['nouveau.runpm', 'video=VGA'])

I don't understand why it does this, but I removed it , updated grub and everything works.