When forcing eDP panel self refresh via 'i915.enable_psr=1' it starts working, but after switching screen resolution, the screen is only visible for a about 1 second, then it becomes black (backlight still on). The only way I have found to get it back to working again without a reboot is standby. This works most of the time, but sometimes (~20%) of the times waking up from standby has the same effect. This is not a new bug, it has been this way ever since PSR started working at all on that hardware. Is there anything I can do to help debug this problem?
PSR is still disabled by default. In current drm-intel-nightly we've started tainting the kernel when debug options like i915.enable_psr are enabled. If you enable things and something breaks, you're on your own. Sorry. That said, maybe you can try drm-intel-nightly branch from [1], IIRC there's some PSR stuff there that's not in v4.3 yet. [1] http://cgit.freedesktop.org/drm-intel
Just built drm-intel-nightly, and unfortunately it does not solve the problem.