Comment 3 for bug 1944094
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| Shaun (drymarchon) wrote Re: Can't adjust screen backlight on Legion Slim 7 AMD | #3 |
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This seems to also effect the Legion 5 15ach6 (AMD) There are two versions of the legion 5, the 2020 version and the 2021 version. It seems that this issue is fixed on the 2020 version by adding the kernel parameter amdgpu.backlight=0 but I can confirm that this does not fix the issue on the 2021 version, so its likely that the 2021 laptop is suffering from whatever this issue is. I'm guessing that the MUX switch is involved in one way or another, as it means that the NVIDIA dGPU does not have to pass frames through the AMD iGPU, it connects to the display separately, and I'm not sure which GPU actually has control over the brightness control. I wonder if the brightness isn't tied to either GPU, maybe its a separate system entirely?