[Intel-xe] [PATCH 3/4] drm/xe/display: Consider has_display to enable it

[Lucas De Marchi]

On Thu, May 11, 2023 at 12:47:26PM +0000, Jose Souza wrote:
>On Wed, 2023-05-10 at 12:54 -0700, Lucas De Marchi wrote:
>> Stop the dance of enabling the display-related driver_features to later
>> disable them on display info init if the platform doesn't have display
>> IP. Besides being needless work, it wasn't covering the ATS-M case that
>> is the same platform as DG2, but without display.
>
>Xe should set pipe_mask = 0 and call i915 functions that will handle no display cases.

in xe, enable_display is the runtime config to be the equivalent of
DRM_XE_DISPLAY=n. It is *not* to meant disabling the display.

history why this ever came to be was:

1) display integration back in the day was less than ideal (still is),
    and developers couldn't test things ignoring display
2) have a way to tell the driver "don't ever touch display IP" for
    bring-up situations.

For (1) we may turn that into "disable display" now, but not for (2).

I'll take a look on how much work it would be to migrate to a
disable-display scenario rather than the simple "Fix ats-m" being done
here.

Lucas De Marchi