[PATCH] drm/i915/display: Clear SEL_FETCH_PLANE_CTL on plane disable

[Nemesa Garg <nemesa.garg@intel.com>]

icl_plane_disable_sel_fetch_arm() wrote SEL_FETCH_PLANE_CTL = 0 only when
crtc_state->enable_psr2_sel_fetch was set. If a plane was disabled after
selective fetch had been turned off, the guard fired early and left the
register's enable bit set in hardware.

The bit is harmless until selective fetch is re-enabled.  When it is, the
hardware resumes fetching for the now-disabled plane and keeps its old DDB
range reserved.

i9xx_cursor_disable_sel_fetch_arm() has the same guard on SEL_FETCH_CUR_CTL
and is fixed the same way.

v2: Add same check for cursor also. [sashiko]

Fixes: b1f5279b5981 ("drm/i915/psr: Move plane sel fetch configuration into plane source files")
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/8739
Assisted-by: GitHub-Copilot:claude-opus-4.6
Signed-off-by: Nemesa Garg <nemesa.garg@intel.com>
---
 drivers/gpu/drm/i915/display/intel_cursor.c       | 15 ++++++++++-----
 .../gpu/drm/i915/display/skl_universal_plane.c    | 15 ++++++++++-----
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c
index 0673f16f6fd0..86bb96ac449b 100644
--- a/drivers/gpu/drm/i915/display/intel_cursor.c
+++ b/drivers/gpu/drm/i915/display/intel_cursor.c
@@ -530,13 +530,18 @@ static int i9xx_check_cursor(struct intel_crtc_state *crtc_state,
 }
 
 static void i9xx_cursor_disable_sel_fetch_arm(struct intel_dsb *dsb,
-					      struct intel_plane *plane,
-					      const struct intel_crtc_state *crtc_state)
+					      struct intel_plane *plane)
 {
 	struct intel_display *display = to_intel_display(plane);
 	enum pipe pipe = plane->pipe;
 
-	if (!crtc_state->enable_psr2_sel_fetch)
+	/*
+	 * Clear this whenever the hardware has selective fetch, not just when
+	 * the current state uses it. The cursor may have been enabled with
+	 * selective fetch earlier and had its enable bit orphaned when the
+	 * feature was switched off.
+	 */
+	if (!HAS_PSR2_SEL_FETCH(display))
 		return;
 
 	intel_de_write_dsb(display, dsb, SEL_FETCH_CUR_CTL(pipe), 0);
@@ -586,7 +591,7 @@ static void i9xx_cursor_update_sel_fetch_arm(struct intel_dsb *dsb,
 		if (crtc_state->enable_psr2_su_region_et)
 			wa_16021440873(dsb, plane, crtc_state, plane_state);
 		else
-			i9xx_cursor_disable_sel_fetch_arm(dsb, plane, crtc_state);
+			i9xx_cursor_disable_sel_fetch_arm(dsb, plane);
 	}
 }
 
@@ -695,7 +700,7 @@ static void i9xx_cursor_update_arm(struct intel_dsb *dsb,
 	if (plane_state)
 		i9xx_cursor_update_sel_fetch_arm(dsb, plane, crtc_state, plane_state);
 	else
-		i9xx_cursor_disable_sel_fetch_arm(dsb, plane, crtc_state);
+		i9xx_cursor_disable_sel_fetch_arm(dsb, plane);
 
 	if (plane->cursor.base != base ||
 	    plane->cursor.size != fbc_ctl ||
diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
index 07a683293352..5cda1ab90e40 100644
--- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
+++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
@@ -879,13 +879,18 @@ skl_plane_disable_arm(struct intel_dsb *dsb,
 }
 
 static void icl_plane_disable_sel_fetch_arm(struct intel_dsb *dsb,
-					    struct intel_plane *plane,
-					    const struct intel_crtc_state *crtc_state)
+					    struct intel_plane *plane)
 {
 	struct intel_display *display = to_intel_display(plane);
 	enum pipe pipe = plane->pipe;
 
-	if (!crtc_state->enable_psr2_sel_fetch)
+	/*
+	 * Clear this whenever the hardware has selective fetch, not just when
+	 * the current state uses it. The plane may have been enabled with
+	 * selective fetch earlier and had its enable bit orphaned when the
+	 * feature was switched off.
+	 */
+	if (!HAS_PSR2_SEL_FETCH(display))
 		return;
 
 	intel_de_write_dsb(display, dsb, SEL_FETCH_PLANE_CTL(pipe, plane->id), 0);
@@ -921,7 +926,7 @@ icl_plane_disable_arm(struct intel_dsb *dsb,
 
 	skl_write_plane_wm(dsb, plane, crtc_state);
 
-	icl_plane_disable_sel_fetch_arm(dsb, plane, crtc_state);
+	icl_plane_disable_sel_fetch_arm(dsb, plane);
 
 	if (plane_has_normalizer(plane))
 		intel_de_write_dsb(display, dsb,
@@ -1641,7 +1646,7 @@ static void icl_plane_update_sel_fetch_arm(struct intel_dsb *dsb,
 		intel_de_write_dsb(display, dsb, SEL_FETCH_PLANE_CTL(pipe, plane->id),
 				   SEL_FETCH_PLANE_CTL_ENABLE);
 	else
-		icl_plane_disable_sel_fetch_arm(dsb, plane, crtc_state);
+		icl_plane_disable_sel_fetch_arm(dsb, plane);
 }
 
 static void
-- 
2.25.1