Dear maintainers, I install non-free nvidia-driver package, and now everything seems fine.
GDM launch is fine. GNOME session is smooth. Firefox is okay, I can watch youtube frustration-free, of course full screen is also okay. uswsusp works, too. suspend-to-RAM and resume works. I enabled C1E and C8, all the C state at BIOS. The syslog size is about 200KB. Please tell me if you want it. I keep them. Regards.