vt newcons breaks resuming from S3 suspend for all graphics cards except those being supported by i915kms, radeonkms and amdgpu. Screen is black at resuming. With sc resuming works just fine. It does not matter whether the open-source freedesktop drivers are being used (pre-radeonkms ATI graphics cards, Matrox, S3, ...) or the proprietary nvidia drivers, sc handles them well, unlike vt.
Just to mention, vt newcons fails no matter whether vesa.ko is loaded or not. Setting hw.vga.textmode="YES" or not also has no effect. OS used for testing is 13.0-RELEASE-p6 on amd64.
Note that vesa.ko has no relationship with vt, so it does not matter if it is loaded or not
Well, when using vt in text mode, it does make a difference if vesa.ko is loaded or not. Because, if it is loaded, then the console display reappears showing the shutdown proceeding when pressing the power button after resuming with a dark screen instead of X Window. If it is not loaded, there is no displaying of the shutdown proceeds, screen stays dark until power off. If vt is in graphics mode, screen always stays dark until power off, then there is no difference of having vesa loaded or not. (Just tested this using SiS and S3 graphics cards. More tests with other graphics cards follow.) BTW, for sc, vesa has to be loaded for successful resume, *except* for Nvidia cards. As said, I'll be doing more tests later to understand the patterns, will report back.