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wdkumdfiddcx

IddCx Driver frame stutters, potentially caused by OS version issues

I am working on a IddCx indirect Display Driver. I have run into a bug that I cant find any reason to blame my own code on. Every two seconds or so IddCxSwapChainReleaseAndAcquireBuffer takes over 100ms, up to 8000ms to complete. It normally takes below 16ms to complete (depends on your frame rate).

I even added timestamps to the IddCx Sample code from Microsoft. It still has this issue, so it cant be a fault with my own code. I have exhausted most of my debugging options.

  • Changing IddCx versions I am compiling with (1.4 to 1.8) by targeting the libs, the headers, and defining the macros (IDDCX_VERSION_MAJOR, IDDCX_VERSION_MINOR, IDDCX_MINIMUM_VERSION_REQUIRED). 1.9 btw doesnt seem to run well, IddCxDeviceInitConfig() fails with Invalid Parameter if I choose version 1.9.
  • Changing which UMDF version I am compiling with (2.25 to 2.33).
  • Changing the Windows SDK version I am using (10.0.19041.0, 10.0.20348.0, 10.0.22000.0, 10.0.22572.0).
  • Swapping my OS to the Insider Program preview version of win11 (currently 22000.588 co_release).

Things I think may be solutions that I need help on.

  • When I am running the Driver, within dxdiag, the display says its using WDDM version 1.3, while my other displays use WDDM version 3.0. WDDM 1.3 is old, so maybe this could be causing issues? How do I tell visual studio to compile my driver to compile with WDDM version 3.0? Does my driver need to WHQL Logo'd first?

  • IddCxGetVersion() returns with version 1801 or 1803 no matter what I change (SDK, IDDCx version, etc), which is from 2018! So what am I doing wrong here to get the OS to choose to use a newer version of IddCx? This may be related to the WDDM version being 1.3 instead of 3.0.

  • Swapping back to Windows 10. I originally swapped to Windows 11 because the WDK dev environment is completely unstable, with the samples sometimes not creating functional drivers, that fail to call into 'EVT_IDD_CX_ADAPTER_INIT_FINISHED', I have confirmed its being compiled incorrectly (sometimes) on windows 10, and the old dlls from earlier that day will still work, but the new dlls will not. So thats why I am staying with Windows 11, I also need to swap to Windows 11 anyways since we should be moving forwards, not backwards.

Solution

  • forgot to close this.

    Realized the issue was that the monitor desktop simply wasnt updating. So the OS was just rendering the desktop less often, resulting in less frames being pushed to the swapchain for me to grab