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Hardware rendering causes window not to be drawn



  • Hi. We have the following problem that I'd love to get some insight on:
    In rare cases, when AA_UseDesktopOpenGL is set to true, the following symptoms appear:

    • Main window isn't drawn (is just a white/black square)
    • App stops writing to log file

    Some additional facts:

    • The main window displays has a QtWebEngine
    • At least some other functionality in the app continues.
    • The 6 reported cases I've seen (there are many more) have all been on Windows and all have nvidia geforce cards.

  • Lifetime Qt Champion

    Hi and welcome to devnet,

    You should check the driver version in use. Some contain bugs that can trigger the kind of behaviour that got reported.



  • TLDR; It's at least not only driver related. From our telemetry I can see that the drivers that those 6 are using are some of the most reliable drivers.

    --

    This is the information I have about the video cards and the drivers:

    • description: "NVIDIA GeForce RTX 2080 SUPER" vendor_id: 4318 device_id: 7809 revision: 161 video_memory: 3221225472 driver { date: "7-5-2020" vendor: "NVIDIA" version: "27.21.14.5167" }
    • description: "NVIDIA GeForce GTX 1050 Ti" vendor_id: 4318 device_id: 7298 revision: 161 video_memory: 3221225472 driver { date: "12-11-2020" vendor: "NVIDIA" version: "27.21.14.6089" }
    • description: "NVIDIA GeForce RTX 2080 Ti" vendor_id: 4318 device_id: 7687 revision: 161 video_memory: 3221225472 driver { date: "12-3-2020" vendor: "NVIDIA" version: "27.21.14.6079" }
    • description: "NVIDIA GeForce RTX 2070 SUPER" vendor_id: 4318 device_id: 7812 revision: 161 video_memory: 3221225472 driver { date: "7-5-2020" vendor: "NVIDIA" version: "27.21.14.5167" }
    • description: "NVIDIA GeForce RTX 2080 SUPER" vendor_id: 4318 device_id: 7809 revision: 161 video_memory: 3221225472 driver { date: "4-23-2021" vendor: "NVIDIA" version: "27.21.14.6627" } }
      gpus { description: "NVIDIA GeForce RTX 2070 SUPER" vendor_id: 4318 device_id: 7812 revision: 161 video_memory: 3221225472 driver { date: "8-12-2020" vendor: "NVIDIA" version: "27.21.14.5206" }

    From our telemetry I can also see that sessions using those drivers are very likely to have activity that tells me the UI is working. In fact 4 of those 5 drivers (all except 5167) are in top 10 most likely to have such activity.

    (According to https://www.tenforums.com/graphic-cards/139746-what-do-numbers-nvidia-driver-mean.html
    The drivers are all for WDDM 2.7, the same DirectX version, same nvidia driver baseline but (5) different versions of drivers).


  • Lifetime Qt Champion

    Interesting analysis, thanks !

    By the way, which version of Qt are you using ?



  • We're using 5.15.2. Had same problems with 5.12.3.


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