Christopher, I appreciate what you are saying, but I don't see the need for a new bug report, indeed I feel that filing a new bug report will make this problem even less likely to be fixed (than it already is) as it will spread out the problem, i.e. make the same/related issues appear as two or more separate ones.  

Like the original filer of the bug, I too have had problems with resuming from hibernation (although this now appears to be fixed - touch wood), sleep and also switching from external monitors to the laptop screen. The only common denominator that I can find is the error: [drm:drm_mode_getfb] *ERROR* invalid framebuffer id

Which is present in all cases. The reason that I have mentioned the power possibly being related, and also the SD card reader is because I am basically clutching at straws and hoping the information may be of use to whomever takes this bug on.

I've just had the problem again, this time after leaving my computer for an extended period of time, the monitors turned off but wouldn't come back on and the computer was unresponsive. This is the first time that it has happened this way. I eventually managed to get the system to respond again by disconnecting all leads and then plugging the power cable in (it had been on battery power) and reinserting all the leads again (the machine in question is a laptop that I frequently use as a desktop PC).

dmesg gave the following:

composite sync not supported
[drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
[70377.728058] [drm:kick_ring] *ERROR* Kicking stuck wait on render ring
[70379.232024] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
[70379.232031] [drm:kick_ring] *ERROR* Kicking stuck wait on render ring
[70380.736053] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
[70380.736060] [drm:kick_ring] *ERROR* Kicking stuck wait on render ring
[70382.240052] [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
[70382.240058] [drm:kick_ring] *ERROR* Kicking stuck wait on render ring

Hundreds of those entries repeating for 6 minutes before I unplugged and plugged in everything again:

usb 5-1: new low-speed USB device number 8 using uhci_hcd
[70891.500828] input: Microsoft Microsoft 3-Button Mouse with IntelliEye(TM) as /devices/pci0000:00/0000:00:1d.0/usb5/5-1/5-1:1.0/input/input19
[70891.501166] generic-usb 0003:045E:0040.000B: input,hidraw0: USB HID v1.10 Mouse [Microsoft Microsoft 3-Button Mouse with IntelliEye(TM)] on usb-0000:00:1d.0-1/input0
[70900.632052] usb 5-2: new low-speed USB device number 9 using uhci_hcd
[70900.831155] input: GASIA PS2toUSB Adapter as /devices/pci0000:00/0000:00:1d.0/usb5/5-2/5-2:1.0/input/input20
 [70900.831277] generic-usb 0003:0E8F:0020.000C: input,hidraw1: USB HID v1.10 Keyboard [GASIA PS2toUSB Adapter] on usb-0000:00:1d.0-2/input0
[70900.856808] input: GASIA PS2toUSB Adapter as /devices/pci0000:00/0000:00:1d.0/usb5/5-2/5-2:1.1/input/input21
[70900.857096] generic-usb 0003:0E8F:0020.000D: input,hidraw2: USB HID v1.10 Mouse [GASIA PS2toUSB Adapter] on usb-0000:00:1d.0-2/input1
[70909.257033] composite sync not supported
[70975.529423] [drm:drm_mode_getfb] *ERROR* invalid framebuffer id
[70975.529430] [drm:drm_mode_getfb] *ERROR* invalid framebuffer id
[70975.564358] composite sync not supported
[70975.880297] composite sync not supported

It definitely seems like all roads lead to [drm:drm_mode_getfb] *ERROR* invalid framebuffer id