Backlight is controlled by 3 ics - u34, u35, u36. They are analog muxes. So Panel_Enable, Panel_Pwm are missing on any supported gpus in discrete graphics mode.
Only thing that ics are doing is select dGPU_sel signal is high, then iGpu is main gpu. If signal is low, then mxm gpu is main.
But signal from mxm doesn't arrive to mux. So it could be shorted or what? Currently I cannot use special tools to make sure that they are dead. Also: Panel_PWR_EN from mxm is arriving to one of muxes, which confirm that bios and dGPU recognize eDP hotplug event, also image is on black screen if light it with flash light
Only thing that ics are doing is select dGPU_sel signal is high, then iGpu is main gpu. If signal is low, then mxm gpu is main.
But signal from mxm doesn't arrive to mux. So it could be shorted or what? Currently I cannot use special tools to make sure that they are dead. Also: Panel_PWR_EN from mxm is arriving to one of muxes, which confirm that bios and dGPU recognize eDP hotplug event, also image is on black screen if light it with flash light
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