[Intel-gfx] [PATCH 02/20] drm/i915: Set PCH as NOP when display is disabled

[Chris Wilson]

Quoting José Roberto de Souza (2018-08-09 01:15:48)
> num_pipes is set to 0 if disable_display is set inside
> intel_device_info_runtime_init() but when that happen PCH will
> already be set in intel_detect_pch().

One major thing missed is that if you disable the displays via modparam,
you need to reap all the BIOS enabled displays and stolen memory that
conflict with our usage. (We ignore the conflict so that means the BIOS
can write into memory we are using elsewhere.) The same bug exists for
outputs we don't recover from the BIOS, which is a regression from
circa 3.2.
-Chris