MacOS – Cannot wake Mountain Lion from safe sleep

I have a late-2010 MacBook Air on which I am running OS X Mountain Lion v10.8.2 with FileVault 2 enabled.

When I try to wake it from safe sleep:

• the panel is backlit but nothing is displayed;

• the light on the ⇪ Caps Lock key is responsive; and

• left alone, the machine eventually powers down (but it resumes in the same state when power is restored).

The only way that I have been able to use the machine again is to hard-reset it (which I never like doing); but upon rebooting, shortly after authenticating there is a kernel panic. The machine then starts normally after the consequent soft-reboot.

Grateful for thoughts on how to identify the cause and/or resolve the problem.

Update 1

Having continuted to search around, I discovered a post in which a similar problem was resolved by:

• disabling safe sleep;
• rebooting;
• removing the hibernatefile;
• rebooting;
• re-enabling safe sleep.

I performed these steps, apparently to no avail. However, it now appears that if I enter my password whilst the screen is backlit and nothing is displayed, my wallpaper is (slowly) revealed together with the normal wake-from-sleep login box. I can't be certain whether this was also true prior to performing the above steps, as I'm not sure that I ever tried entering my password at the blank screen.

Sadly, that's as good as it gets: neither a mouse pointer nor keyboard cursor are visible on the screen; and the keyboard is unresponsive. The clock, battery status and WiFi icons in the top-right of the screen all remain in their pre-sleep states and do not update; if the computer is left for long enough, there is eventually a kernel panic (apparently related to the graphics drivers?).

Update 2

Following @danielAzuelos's suggestion, I ran Apple Hardware Test (from the Software Reinstall Drive) in extended mode, but no faults were identified.

Neither USB port is in use.

I discovered that the problem does not manifest when DestroyFVKeyOnStandby=0, so there is almost certainly something wrong with how my hibernating MacBook configures EFI to wake.

I have discovered that, if the machine goes into safe sleep when attached to an external display, everything works exactly as it should (even if the external display is no longer attached on wake).