2011 13 MBP i5 ***debug info for apparent hang in main graphics engine ***

Question

*debug info for apparent hang in main graphics engine *
console is giving me this message and it is affecting my MBP's ability to wake from sleep correctly. I get either a dark screen or scrambled graphics and have to hold the power button to re-boot.
(I do have an external display hooked up to the MBP, this was never an issue with all my past Macbooks.)

Answer 1

My 15" MBP 15 Core i7 has the same problem. Spoke with AppleCare and tried resetting to power management unit and the PRAM; no improvement. Also tried reinstalling the 10.6.7 'early 2011 macbook pro' update - still no change.
Each attempt at waking from sleep produces a series of the same error messages in Console. Here's the full series:
kernel WaitForStamp: Overflowed waiting for stamp 0x70ed on Main ring: called from
kernel timestamp = 0x70eb
kernel ** Debug info for apparent hang in Main graphics engine **
kernel ring head = 0x00200eb4, wrap count = 0x 1
kernel ring tail = 0x000010e0 ring control = 0x00003801 enabled, auto report disabled, waiting, semaphore not waiting, length = 0x004 4KB pages
kernel timestamps = 0x70eb
kernel Semaphore register values:
kernel VRSYNC: (0x12044) = 0x70eb
kernel BRSYNC: (0x22040) = 0x0
kernel RVSYNC: (0x 2040) = 0x0
kernel BVSYNC: (0x22044) = 0x0
kernel RBSYNC: (0x 2044) = 0x0
kernel VBSYNC: (0x12040) = 0x0
kernel Looks like Main ring is stuck waiting on an event
kernel After attempt to clear wait condition = 0x00003001 no longer waiting
kernel kIPEHR: 0x2000000
kernel kINSTDONE: 0x882fbb
kernel kINSTDONE_1: 0x2308a3f
Re-sleeping and re-waking the machine occasionally lets the screen come back on.
The machine itself is running; I can ssh into it from another computer.
I tried disabling hibernation, too (http://danwarne.com/how-to-turn-off-slow-sleep-hibernate-mode-on-a-macbook-pro/), with no change.
Anyone with new information on the issue? Going to take it to the Apple Store, I suppose, once I have time...