[Intel-gfx] [PATCH v3 2/2] drm/i915/skl: distribute DDB based on panel resolution

[Chris Wilson]

Quoting Mahesh Kumar (2018-08-01 16:11:13)
> We distribute DDB equally among all pipes irrespective of display
> buffer requirement of each pipe. This leads to a situation where high
> resolution y-tiled display can not be enabled with 2 low resolution
> displays.
> 
> Main contributing factor for DDB requirement is width of the display.
> This patch make changes to distribute ddb based on display width.
> So display with higher width will get bigger chunk of DDB.
> 
> Changes Since V1:
>  - pipe_size/ddb_size will not overflow u16 so use appropriate
>    data-types during computation (Chris)
> Changes Since V2:
>  - avoid redundancy and possible truncation errors (Chris)
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107113
> Cc: raviraj.p.sitaram at intel.com
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Mahesh Kumar <mahesh1.kumar at intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris