Unable to disable Mosaic mode on some video cards


I’m the author of DisplayMagician, and some of my users are having trouble disabling Mosaic. It works perfectly fine on my machine (and many of my users), but some users are reporting that they are unable to disable Mosaic using NvAPI_Mosaic_EnableCurrentTopo(0). The driver returns a NVAPI_MODE_CHANGE_FAILED error when this happens.

The error only happens when disabling the Mosaic with NvAPI_Mosaic_EnableCurrentTopo(0).The exact call is here: NVIDIAInfo/NVIDIALibrary.cs at v1.3.8 · terrymacdonald/NVIDIAInfo · GitHub (if you’re interested in seeing the surrounding code)

I am a Public API user (though interested in whether I can join the developer programme to get access to the docs).

Can you please tell me what the NVAPI_MODE_CHANGE_FAILED error means, what the NVAPI driver checks when performing the NvAPI_Mosaic_EnableCurrentTopo(0) call, and some ideas about what I am missing?


Dear @terry.macdonald

Thank you for contacting NVIDIA developer forum.
We have sent your query to the respective team for details and we will get back to you on same. However, the concerned developer is on leave at present. So we will have some delay in getting a response. Thanks for your understanding.

NVAPI Forum Moderator

No problem. It’s important to have a good work/life balance.