Bug: Second and third display _both_ disabled at boot if they have different refresh rates and _one_ of them is powered off

Gaming and Visualization Technologies General Topics and Other SDKs Drivers - Linux, Windows, MacOS
1

GPU: RTX 4090
Driver: 527.37

I am observing a strange multi-monitor issue only occurring during boot, related to refresh rate:

My second monitor runs at 60Hz. I have a TV connected as a third monitor, and if it is set to 60Hz as well, everything works fine.

However, if my TV is set to a refresh rate other than 60Hz, e.g. 120Hz and is powered off, my second monitor gets disabled during boot.

Steps to reproduce:

  • Connect two monitors and a TV.
  • Set the second monitor to 60Hz.
  • Set TV to a different refresh rate, e.g. 120Hz.
  • Confirm that all screens are working at their respective refresh rates.
  • Power off the TV.
  • reboot the PC.

Result:

  • First screen powered on and enabled.
  • Second screen powered on but not enabled (blank screen, shows up in Windows and Driver as deactivated)
  • TV powered off and also not enabled.

Notes:

  • Powering on the TV after rebooting will re-enable both the TV and the second screen.
  • The second screen should be independent of the power state of the TV, yet seems not to be.
  • The problem occurs only if they have different refresh rates. If I set my TV to 60 Hz, power it off, and reboot, the second screen remains enabled.
  • The high resolution is not the issue. If I set the TV to 59 Hz, and power it off, the second monitor is also disabled during reboot until the TV is powered.
  • I believe this should be reproducible with any three screens. With a TV as the third screen, it can be ensured that it remains powered off during reboot, such that the issue can be reproduced reliably.
  • The refresh rate of the first monitor seems to be no issue. My first monitor runs at 144Hz, a different refresh rate than the second monitor.
  • While all three monitors are powered, running them at different refresh rates works fine.
2

Hi there @NotSpecial and welcome to the NVIDIA developer forums!

Much of the Multi-Monitor setup s handled by the Windows Display manager, which can do all kinds of curious things, partly out of control of the NVIDIA driver.

For example, in the error case when the second monitor is disabled. What happens if you disable it at this point? Can you enable it.

Then keep the TV off and reboot and check what happens. I expect both first and second monitor will come up as expected.

Windows stores different multi-monitor configurations. Possibly it stored a setting where exactly this Monitor/Refresh rate combination disabled the second monitor.

Sadly this is nothing that can be controlled directly on a driver level since the driver has no context information about the intended setup. It only reports available output devices with available settings parameters to the operating system and its window and display manager, which in turn decides which of those to use and how to set them up.

Thanks!