https://bugzilla.kernel.org/show_bug.cgi?id=67121
--- Comment #10 from Alex Deucher alexdeucher@gmail.com --- (In reply to Adrian Knoth from comment #9)
Maybe, but then again, why does with work on a freshly booted machine (before first suspend). And last not least, why isn't UMS affected?
UMS runs the bios post to re-init the gpu on resume while kms re-inits the hw itself. Presumably the bios post does something else to the system which prevents the issue.