drm/i915: Account for scale factor when calculating initial phase
authorVille Syrjälä <ville.syrjala@linux.intel.com>
Wed, 14 Nov 2018 13:32:55 +0000 (15:32 +0200)
committerJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Thu, 15 Nov 2018 11:57:20 +0000 (13:57 +0200)
commit6e8adf6f4a4fa57dd3bef6b70de96e2b7b311204
treec718f7455da456bf8eb64df62965c77b68a8d456
parent27971d613fcb5b6ad96320bc4f2c90f4d4fde768
drm/i915: Account for scale factor when calculating initial phase

To get the initial phase correct we need to account for the scale
factor as well. I forgot this initially and was mostly looking at
heavily upscaled content where the minor difference between -0.5
and the proper initial phase was not readily apparent.

And let's toss in a comment that tries to explain the formula
a little bit.

v2: The initial phase upper limit is 1.5, not 24.0!

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 0a59952b24e2 ("drm/i915: Configure SKL+ scaler initial phase correctly")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181029181820.21956-1-ville.syrjala@linux.intel.com
Tested-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Tested-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> #irc
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> #irc
(cherry picked from commit e7a278a329dd8aa2c70c564849f164cb5673689c)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
drivers/gpu/drm/i915/intel_display.c
drivers/gpu/drm/i915/intel_drv.h
drivers/gpu/drm/i915/intel_sprite.c