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[RIFT CV1] mostly (but not only) green noise and horizontal lines appearing with a ROG Notebook (GTX

krasniy_krasniy_ Posts: 2
NerveGear

Hello.


Sometimes an RGB noise but mostly green points covers the whole view and sometimes a very thick white horizontal line pops up and disappears. Sometimes the screen goes completely black. Seems like a weak video signal to me.

This Rift works fine on another Desktop PC with GTX980, but when I try on this ROG notebook with GTX 1070 this always happens.

Nonetheless I tried a different Rift video/data cable and the issue persists.

This exact same thing also happened with another Rift CV1 I owned.

I tried updating the GPU drivers on it, installing GeForce Experience and updating, and today also did a reboot of Windows 10 which downgraded the GPU driver I believe. Issue is still there.

I thought maybe it has something to do with connecting the Rift to the HDMI port rather than miniDP. I'm pretty sure the GTX1070 is used with HDMI and not the onboard GPU but maybe it goes through the motherboard somehow and that weakens the signal or can't handle 90Hz?

So I I actually tried not one but two different HDMI to miniDP adapters and none worked. Only audio comes but i think its from the USB anyway.

These are the adapters: https://i.imgur.com/j0giKdL.jpg

I disassembled both to see what's inside and both have ICs, but not converters. One is unmarked IC, the other is this: https://i.imgur.com/unFvotg.jpg

Googling it it seems like a simple "level shifter" ( https://en.wikipedia.org/wiki/Level_shifter ) which I don't think should introduce latency or be resolution/Hz limited. But if it is please let me know of a more suitable HDMI to miniDP adapter, if you think this might be the issue.


The specific model of the notebook is ROG G752VS. It can run most modern games in high settings.


The GPU can output 120Hz to 240Hz 1080p to a low latency Alienware 240Hz monitor but by my tests only the DisplayPort connector provides clean frames at 1080p 120Hz or up, the HDMI port works at 240Hz but the signal keeps getting lost and reappearing and there's some pixel noise similar but not exactly the same looking as inside the Rift. This fact may provide some clues.


If, on the other hand, you believe this is a driver issue and/or is a known driver issue with such notebooks, please let me know what version of the driver to try.



Thank you.


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Comments

  • LZoltowskiLZoltowski Posts: 6,617 Volunteer Moderator
    Not all Mini DP to HDMI cables are the same, it depends what HDMI signal is coming out, many are just capable fo 1080p (HDMI 1.3 standard) and don't have enough bandwidth .. I have seen Active DP to HDMI 2.0 ones work better, they are capable of a lot more bandwidth.
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  • krasniy_krasniy_ Posts: 2
    NerveGear
    edited September 2018
    I don't think a level shifter IC depends on bandwith at all. maybe Oculus just doesn't work with DP?
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