[PATCH 5.15 099/107] drm/i915: Skip wm/ddb readout for disabled pipes

[Greg Kroah-Hartman]

From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>

commit 0211c2a0ea600e25db3044daaeff4fe41c3ed6d9 upstream.

The stuff programmed into the wm/ddb registers of planes
on disabled pipes doesn't matter. So during readout just
leave our software state tracking for those zeroed.

This should avoid us trying too hard to clean up after
whatever mess the VBIOS/GOP left in there. The actual
hardware state will get cleaned up if/when we enable
the pipe anyway.

Cc: stable@xxxxxxxxxxxxxxx
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5711
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220617195948.24007-1-ville.syrjala@xxxxxxxxxxxxxxx
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
(cherry picked from commit b183db8f4783ca2efc9b47734f15aad9477a108a)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/i915/intel_pm.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6638,7 +6638,10 @@ void skl_wm_get_hw_state(struct drm_i915
 		enum plane_id plane_id;
 		u8 slices;
 
-		skl_pipe_wm_get_hw_state(crtc, &crtc_state->wm.skl.optimal);
+		memset(&crtc_state->wm.skl.optimal, 0,
+		       sizeof(crtc_state->wm.skl.optimal));
+		if (crtc_state->hw.active)
+			skl_pipe_wm_get_hw_state(crtc, &crtc_state->wm.skl.optimal);
 		crtc_state->wm.skl.raw = crtc_state->wm.skl.optimal;
 
 		memset(&dbuf_state->ddb[pipe], 0, sizeof(dbuf_state->ddb[pipe]));
@@ -6649,6 +6652,9 @@ void skl_wm_get_hw_state(struct drm_i915
 			struct skl_ddb_entry *ddb_uv =
 				&crtc_state->wm.skl.plane_ddb_uv[plane_id];
 
+			if (!crtc_state->hw.active)
+				continue;
+
 			skl_ddb_get_hw_plane_state(dev_priv, crtc->pipe,
 						   plane_id, ddb_y, ddb_uv);