Commit 0701c285 authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/i915: Stop loading linear degamma LUT on glk needlessly 



Make glk_load_luts() a bit lighter for the common case
where neither the degamma LUT nor pipe CSC are enabled
by not loading the linear degamma LUT. Making .load_luts()
as lightweight as possible is a good idea since it may need
to execute from a vblank worker under tight deadlines.

My earlier reasoning for always loading the linear degamma LUT
was to avoid an extra LUT load when just enabling/disabling the
pipe CSC, but that is nonsense since we load the LUTs on every
flagged color management change/modeset anyway (either of which
is needed for a pipe CSC toggle).

We can also get rid of the glk_can_preload_luts() special
case since the presence of the degamma LUT will now always
match csc_enable.

v2: Fix typos (Uma)

Reviewed-by: default avatarUma Shankar <uma.shankar@intel.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221024161514.5340-6-ville.syrjala@linux.intel.com
parent 48205f42

drivers/gpu/drm/i915/display/intel_color.c

+3 −23
Original line number Diff line number Diff line
@@ -1198,24 +1198,6 @@ static bool chv_can_preload_luts(const struct intel_crtc_state *new_crtc_state) 
	return !old_crtc_state->post_csc_lut;

}



static bool glk_can_preload_luts(const struct intel_crtc_state *new_crtc_state)

{

	struct intel_crtc *crtc = to_intel_crtc(new_crtc_state->uapi.crtc);

	struct intel_atomic_state *state =

		to_intel_atomic_state(new_crtc_state->uapi.state);

	const struct intel_crtc_state *old_crtc_state =

		intel_atomic_get_old_crtc_state(state, crtc);



	/*

	 * The hardware degamma is active whenever the pipe

	 * CSC is active. Thus even if the old state has no

	 * software degamma we need to avoid clobbering the

	 * linear hardware degamma mid scanout.

	 */

	return !old_crtc_state->csc_enable &&

		!old_crtc_state->post_csc_lut;

}



int intel_color_check(struct intel_crtc_state *crtc_state)

{

	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
@@ -1626,11 +1608,9 @@ static void glk_assign_luts(struct intel_crtc_state *crtc_state) 
	 * On GLK+ both pipe CSC and degamma LUT are controlled

	 * by csc_enable. Hence for the cases where the CSC is

	 * needed but degamma LUT is not we need to load a

	 * linear degamma LUT. In fact we'll just always load

	 * the degama LUT so that we don't have to reload

	 * it every time the pipe CSC is being enabled.

	 * linear degamma LUT.

	 */

	if (!crtc_state->pre_csc_lut)

	if (crtc_state->csc_enable && !crtc_state->pre_csc_lut)

		drm_property_replace_blob(&crtc_state->pre_csc_lut,

					  i915->display.color.glk_linear_degamma_lut);

}
@@ -1671,7 +1651,7 @@ static int glk_color_check(struct intel_crtc_state *crtc_state) 


	glk_assign_luts(crtc_state);



	crtc_state->preload_luts = glk_can_preload_luts(crtc_state);

	crtc_state->preload_luts = intel_can_preload_luts(crtc_state);



	return 0;

}