Random black screens on monitor connected via DP only when TV is connected via HDMI

So, it turns out this is a known issue for "some time" now, for a rather large group of nvidia card users, but even though i spent "a bit" of my time on learning how to fix this, i've found that no solution is guaranteed. One of the first mentions about this issue i've found dates back to the year 2013.

The issue: random black screen similar to when 'out of range'/'no signal' but without those dialogue boxes appears for 2-3 seconds. Absolutely at random times. Then fter 2-3 sec everything back to normal.

So my setup is this:
1. win 10 x64 build 1909
2. One monitor (specifically Asus MG279Q) is connected via Displayport to the Palit 1070 GTX.
144Hz 2560x1440p 8 bit RGB full
3. One TV (Sony 55XF9005) is connected via HDMI to the same nvidia card

It happens only when TV is connected to the card. If i unplug the cable OR disable TV as the output in the Nvidia control panel "Set up multiple displays" section black screen issue disappears. The sate of TV doesn't matter - turned On or Off - black screen still randomly happens.

The things i've tried to fix this issue, but which did not help. In no particular order:
0. Tried three different DP cables, one of which was DP-miniDP and two different HDMI cables. And a combination of them. Didn't hlep
1. Tried Samsung 2243NWX monitor with VGA to DP adapter - still black screens
3. Reinstall defferent driver versions with full cleaning via DDU. Did it several times with 6-7 different driver versions dating back to the year 2018. Did not install HD Audio/3D/ansel or geforce experince. Only NVCP and driver itself. Didn't help
4. Removing overclock/uninstalling MSI Afterburner. All driver installations which i made were on stock gpu clocks. Didn't help. Besides, if i unplug TV cable from HDMI port it solves the issue, thus i don't think overclock is the problem.
5. Changing to different resolution, like 1024x768 30Hz. Didn't help
6. Disabling HPET on/off in BIOS
8. Disabling/enabling fast boot in BIOS. Current sate is disabled, not a fan of this buggy thing
8. Created custom resolution with CRU - did not help
9. Disabled DDC/CI in monitor settings - didn't help
10. In powermanagement in windows monitor is set to never go to sleep.
11. In monitor on-screen settings ECO mode is turned off
12. No other timers/or power saving features are turned on in monitor on-screen settings
13. The "supposed fix" for very simillar problem - turning of power cable and DP cable and waiting 30 sec and rebooting PC. After reboot plugin cables back. Didn't help

Two important things to note:
1. The monitor itself does not cause this problem - when it's the only device connected to the 1070 everything is fine. Or when it is connected to another computer everything is fine too. No black screens. I also tested old Samsung 2243NWX with VGA to DP adapter and black screens happen on it too.

2. The 1070 itself does not cause the issue - i play several game titles both on the Asus monitor and on Sony TV and neither of them shows any glitches/black screens/fps drops or any other abnormal behaviour when only one device is active in the NVCP in "set up multiple displays" section. Games run either fullscreen or windowed so it's quite good indicator that card itself is allright.


So after reading several threads which google provided me on my "random black screen nvidia" query, i 99% sure that this issue is some blatant, 'elephant in the room' oversight in the driver.
I tend to agree with some other poor man with this problem who thinks that the cause of the issue is driver check for P-state of the monitor/TV which somehow is interconnected between HDMI and DP ports on the card and for some reason sends signal to power off monitor for 2-3 sec. I would really like to talk to the person who wrote the code to pefrorm this procedure in same cycle for both ports, in non-independent manner between the two. I understand why the check for power state is done simultaneously, i don't understand why one port should affect the other. And i don't understand why output to DP port should be affected by negative/positive repplies for such P-state checks.

A few links of other nvidia users who experienced same issue(there are many more in google results):
https://www.nvidia.com/en-us/geforc...ll-people-with-black-screensno-signal-issues/
https://sites.google.com/site/ebobster/stuff/displayportblanking - dates back to 2013(!) what the hell?


I hope that everyone agrees that in 2020 one should not go in NVCP to check/uncheck his TV everytime he wants to watch his TV or play some computer games on big screen like Mortal kombat and other.
I also believe that watching TV connected to HDMI should not cause blinking black screens on computer monitor connected to DP port at the same time. One have to turn off his PC monitor entirely to peacefully watch movie/tv-series.

If anyone of you experienced this issue and found a fix, i would gladly hear your solution.
For me the only solution seems to be isolating 20th and 19th pins in DP cable. Even the cable which came with Asus MG279Q from the box has those pins!

Obi-W... ManuelG, you are my only hope.

ps the issue should be easy to replicate i guess...? Just plug-in yor TV via HDMI and have your monitor connected via DP

 

The only situation i have seen an intermittent black screen issue over HDMI, is if you output 4k @ 60hz Full-RGB 8-bit uncompressed chroma (4:4:4) over an HDMI 2.0 connection.

Disabling the TV's sound device in the Windows Sound Control Panel (or NVCP) solved the issue for me, but this was with an LG 4k TV. Try it and see if it works for you, otherwise i assume its a HDMI handshaking issue between the graphics card and the Sony 4k TV.

Seeing as the amount of data to transport 4k/60hz RGB 4:4:4 is about 17.82gbps, that is edging up against the limit of the HDMI 2.0 spec which is 18gbps. It could be the sound that is using just enough additional bandwidth to cause the signal to fluctuate, or the build quality of the HDMI cable you are using isn't handling the bitrate required and causing errors.

 

Thanks for your suggestion! Even though i have black screen on my asus monitor connected with display port and not on TV, i still tried your advice. Even disbled all other audio devices in the device manager - unfortunately it didn't help. Sad smiley.

 

Seeing as you have done all of this already, unless i have missed it somewhere in your explanation of what you have done so far, if you haven't used another HDMI display along with displayport monitor, that would be my next recommendation to rule out possible HDMI handshaking issues with the TV.

If you can test on a different 4k TV, even better. But if it stops intermittently losing the picture on a different HDMI display of any resolution, then in theory the problem lies either with the Sony 4k TV itself or the bandwidth from the graphics card divided to a displayport monitor and a 4k TV is not enough your situation.

 

What country are you in? Does the TV have an earth connection?

If so, are the two devices plugged into the same power strip/wall socket 'set'? If not, could it be a poor earth connection on one side?

You can get pretty cheap wall socket testers here in the UK, which let you know if the wiring is correct on the socket.

 

I would suggest giving a try to this https://www.nvidia.com/en-us/drivers/nv-uefi-update-x64/

You might find a thread on reddit with same problem solved by this, if I remember correctly.

Haven't seen you've done this update, hence the idea.