Hooray! I’ve finally fixed my MacBook Pro’s problems with waking up from sleep!
Basically, about one time in ten, my Mac would only partly wake up from a state of sleep. Nothing would revive it, so I’d have to reboot. That was very annoying, and multiple web searches over the past few months offered no help whatsoever until I discovered this page on how to change the sleep mode. So now my Mac is set to sleep mode 0 (i.e. the “old style sleep mode, with RAM powered on while sleeping, safe sleep disabled, and super-fast wake”) instead of the currently standard sleep mode 3 (i.e. the new sleep mode where “RAM is powered on while sleeping, but RAM contents are also written to disk before sleeping” so that the machine hibernates if power if totally drained).
The lack of ability to slip into hibernation as a backup isn’t a problem for me, since I never fully run down my battery while in sleep mode. Plus, I like that the computer sleeps and wakes faster than before. Most importantly, however, my computer has woken up perfectly from sleep for a few weeks now, with just one funky exception. Until it began working properly, I didn’t realize how much the constant nagging worry that my computer might not wake properly wore on me! Now I feel liberated!