We have a misunderstanding. Tonemapping is HDR->LDR, EyeAdaptation is normalizing the HDR based on content.
I explained how to disable eye adaptation. Tonemapping is still happening. Our tonemapper pass also does add noise to reduce color quantization for 8 bit, apply color grading from LUT texture and other things. All that also works together with otehr features e.g. TemporalAA which assumes a tonemapping step.
If you disable tonemapping (=linear tonemapper) you would get clamped highlights. That looks quite bad.
If you want to export some color like GBuffer properties - you don’t need to disabale the tonemapper, you can access the HDR intermediate.
You also can change PostProcessTonemap.usf.
We intend to make the postprocessing more programable - then you can do such a change in the material editor.