[Intel-gfx] [PATCH v2 26/27] drm/i915/xe2lpd: Write DBuf after CDCLK change in post plane

[Lucas De Marchi <lucas.demarchi@intel.com>]

From: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

Previously we always updated DBuf MBUS CTL and DBUF CTL regs after
CDCLK has been changed(CDCLK_CTL), however for Xe2-LPD we can't do like
that anymore. According to BSpec, we have to first update DBuf regs and
then write CDCLK regs, when CDCLK is decreased, which we do in post
plane.

So now we do CDCLK post plane update only after DBuf regs are
written (CDCLK/MDCLK separation requires MDCLK/CDCLK ratio to be written
to DBuf regs).

Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 83e1bc858b9f..b0455d5d9bfd 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -7039,7 +7039,7 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 	/* Now enable the clocks, plane, pipe, and connectors that we set up. */
 	dev_priv->display.funcs.display->commit_modeset_enables(state);
 
-	if (state->modeset)
+	if (state->modeset && DISPLAY_VER(dev_priv) < 20)
 		intel_set_cdclk_post_plane_update(state);
 
 	intel_wait_for_vblank_workers(state);
@@ -7086,6 +7086,9 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 	intel_dbuf_post_plane_update(state);
 	intel_psr_post_plane_update(state);
 
+	if (state->modeset && DISPLAY_VER(dev_priv) >= 20)
+		intel_set_cdclk_post_plane_update(state);
+
 	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
 		intel_post_plane_update(state, crtc);
 
-- 
2.40.1