Same problem here (T23 with SuperSavage IX/C SDR) - I'm able to recover by closing and re-opening the lid again after resume - seems to be just an issue with screen switching. I also recognize that Fn-F7 does not work with Gutsy while it worked with Feisty. In Feisty I sometimes had to press Fn-F7 to get the display back again after resume.
Same problem here (T23 with SuperSavage IX/C SDR) - I'm able to recover by closing and re-opening the lid again after resume - seems to be just an issue with screen switching. I also recognize that Fn-F7 does not work with Gutsy while it worked with Feisty. In Feisty I sometimes had to press Fn-F7 to get the display back again after resume.