Extended Display and 2 GPU's

[dimipisi]

@ledoge First of all I want to thank you for your work and for this product. It is trully a great tool and it saved me the trouble and money because I was set on buying a new monitor before finding this tool!

Now, the problem I encountered. My laptop has 2 GPU's. An integrated one and a dedicated one. My laptop is always in hybrid mode because I usually use my laptop on different places and I need the battery life when I'm on the go. If the laptop is in hybrid mode, when I use both monitors at the same time (in extended mode), both monitors are assigned the same number (1) in DWM_LUT. This causes the program to assign the lut but a few seconds later the screen goes black and then the program goes to the state of "inactive". If I disable hybrid mode (dedicated gpu only), the program assigns different numbers to the displays, Laptop display number one and external display number 2, and the luts are applied.

Maybe a simple fix would be to not allow the program to assign the same number to different monitors. If a number is already assigned, then the program assigns a different number.

iGPU + dGPU (same number applied to both monitors)

dGPU only (different number applied to the monitors)

[ledoge]

Thanks!

Very interesting issue. The number shown is just used in the GUI, not internally, so that's not the cause of the issue. However, that value, as reported by Windows, should normally be unique, so there's definitely something strange going on behind the scenes. If I had to guess, maybe the Desktop is actually rendered on the dedicated GPU for the external monitor? In that case, only having a LUT assigned to one of the monitors should work fine – please let me know if that's right. Unfortunately, as I don't have a Laptop with a dedicated GPU, I can't really troubleshoot and fix the crash. If my guess is right, it would require a fair amount of changes to the code, so not feasible unless I can actually test it locally.

[dimipisi]

Yeah, the external display is controlled by the dedicated GPU, so I assume the issue is probably related to the process being applied on two different gpu's at the same time. I'll try and only apply a lut to one display when in extended mode, and tomorrow i'll tell you the result.

Thanks!

[dimipisi]

@ledoge So, I tried to apply only one lut to one monitor and here are the results.

If I apply only one lut to the laptop display, it fails. But if I only apply the lut to the external display, it works.

But then I remembered something. I went to the windows settings and switched my laptop screen to be the main display. Now DWM_LUT only stays active if I apply the lut only to the laptop display. So, it works only on the main display selected in the windows settings.

Running Win10.