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DK2, new PC, black strobing

boggers
Honored Guest
I have a freshly installed Win 7 64bit PC, running Unity 5.2.2p4 which I "downgraded" after 5.3.1f1 had the same issue.

When running a preview in the Unity editor, I get black flashes in the DK2 whenever the scene is in any way complex, it looks similar to screen tearing except instead of the previous frame left behind it is black, which is very quickly headache inducing. A compiled exe of the same scene seems to run OK.

Anyone have any idea what may be causing this?

Quicklog from the OVR Config Util

Display Driver Version: 1.2.8.0
Positional Tracker Driver Version: 1.0.14.0

NVIDIA GeForce GTX 750 Ti
Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz

HMD Firmware: 2.12

Connected to OVRService server.


Edit: After much gnashing of teeth, I've discovered that having a monitor plugged into a VGA port causes the black flickering on the DK2, as well as other issues with DirectX not being able to access SharedResources which cascaded into a whole bunch of errors. Weird, right?

Swapped the monitor out for a DVI one, and everything works fine.
3 REPLIES 3

boggers
Honored Guest
Update, so I marked this as resolved before, but it really wasn't. Changing monitor ports reduced the problem significantly but did not eliminate it.

The black flashing still appears, not not only in the Unity preview but in any VR app that pushes the CPU / GPU at all. It also seems to be *maybe* GPU heat related, as it tends to happen more often, and worse, after the Rift has been in use for a while.

It really looks as though whenever a frame is dropped, the rift display shows black instead of holding the previous frame, which means either half-screen flashes instead of screen tearing, or a few things appear to be using VSync, so that every 2nd frame is black.

Anyone have any ideas? It does seem to have good days and bad days, but right now it's practically unusable.

cybereality
Grand Champion
Do you have the latest Nvidia drivers? I recall some old drivers did have flickering issues.

Also, since you say switching ports helped, have you thought about getting new cables and adapters completely?

Why were you using VGA? Is you monitor really that old in doesn't have a better port? Do you have a more modern monitor you can swap in as a test (for example, one that can use a native digital connection)?
AMD Ryzen 7 1800X | MSI X370 Titanium | G.Skill 16GB DDR4 3200 | EVGA SuperNOVA 1000 | Corsair Hydro H110i Gigabyte RX Vega 64 x2 | Samsung 960 Evo M.2 500GB | Seagate FireCuda SSHD 2TB | Phanteks ENTHOO EVOLV

boggers
Honored Guest
The monitors I was originally using had only a HDMI and VGA port, and we had no HDMI to DVI adapters. The video card had HDMI, 2x DVI (I think DVI-D? the one without holes for the analog pins, so you can't use it with a VGA to DVI adapter) and a VGA. Since the rift was on the HDMI, it left only the VGA.

Since then I have swapped out for two monitors with DVI inputs so everything is direct, no adapters, and initially that did seem to fix things, but the flickering still happens intermittently.

Interestingly, Notch's mandelbox running in WebVR in Firefox nightly is the only thing I've seen so far that has the 'vsync' effect, ie very consistently, every 2nd frame is completely black rather than the occasional half black frame, but what is really odd there is that the health and safety warning renders solidly over the top, while the scene flashes behind it. I'm unsure if that behavior is the same in other apps as the warning usually disappears before it starts flickering.

I had the latest drivers at the time of posting, and updated them again today before posting, just in case.

Since it did initially seem that other monitors were having some effect I've tried with only a single monitor, with no improvement.

At this point I'm starting to think I should test with a different video card, but that will mean pulling it out of someone else's PC. 😕