Suspend problem on T420

[VanZan]

I have two T420 laptops. The newer one, without a fingerprint reader thingy, can suspend without any problems in Ubuntu. The older T420, that has a fingerprint reader, also running Ubuntu just won't suspend. The screen goes black but then suddenly comes back and I'm at the lock screen.

Can't understand for the life of me why! I don't know if it's down to the fingerprint reader but that's the easiest way I have of telling them apart. Would love to get a solution as I find the suspend option very handy.

Thanks!

:edit: After writing this I went into the BIOS and disabled a few things (mostly to do with the fingerprint reader) for a laugh and now suspend seems to be working!! Gosh I'm good!!! Pure dumb luck.

[RealBlackStuff]

To completely get rid of the FPR (highly advisable), remove the palmrest, then either cut (not so good) or disconnect the cable from the FPR (best).
Then go to the pub and have a pint of the Real Black Stuff to celebrate.

[VanZan]

lol thanks but it seems I spoke too soon. Started up the laptop this morning and suspend doesn't work again. It was working grand the first time I booted up after rooting around in the BIOS.

[jaspen-meyer]

Bad ram will cause suspend problems.

Try this:
http://memtest86.com/

Also, if it finds anything, you can use the BadRAM option of MemTest which'll list the bad sections of ram in a format compatible with Grub's BadRAM. Take those values and write them to /etc/default/grub (or someplace where you can feed the values to your kernel/bootloader).