(In reply to Timo Valtoaho from comment #6)
> git bisected this to d57c0edfe00d3274b50f91ce3076ed0e82d28782.

commit d57c0edfe00d3274b50f91ce3076ed0e82d28782
Author: Alex Deucher <alexander.deucher@amd.com>
Date:   Wed Jul 8 14:08:12 2015 -0400

    Revert "Revert "drm/radeon: dont switch vt on suspend""

    This reverts commit ac9134906b3f5c2b45dc80dab0fee792bd516d52.

    We've fixed the underlying problem with cursors, so re-enable
    this.

That is interesting as I have a Radeon 6450 which displayed "strange" colors
after suspend (often but not always) and the problem was caused exactly by the
same commit. However with my card I never had problems with HDMI audio after
suspend.

I never filed a bug report as I could work around the issue by switching the VT
manually (e.g. Ctrl+Alt+F2 / Ctrl+Alt+F1). Even better: After moving to Wayland
(F25) I did not notice the bug anymore.