[PATCH v3] drm/{i915, xe}/display: add core workaround query to display parent interface

There are workarounds display needs to apply depending on information
only available to the core driver. Add a display parent interface for
the query. For starters, there's only one workaround like this, so keep
it simple instead of over-engineering.

This lets us drop an #ifdef I915 as well as xe dependency on some
display headers.

v2: git add xe_display_wa.h

v3: Add a comments about usage (Suraj)

Reviewed-by: Suraj Kandpal <[email protected]>
Signed-off-by: Jani Nikula <[email protected]>
---
 drivers/gpu/drm/i915/display/intel_display_wa.c |  4 +++-
 drivers/gpu/drm/i915/display/intel_display_wa.h |  9 ---------
 drivers/gpu/drm/xe/display/xe_display.c         |  2 ++
 drivers/gpu/drm/xe/display/xe_display_wa.c      | 13 +++++++++----
 drivers/gpu/drm/xe/display/xe_display_wa.h      |  9 +++++++++
 include/drm/intel/display_parent_interface.h    | 10 ++++++++++
 6 files changed, 33 insertions(+), 14 deletions(-)
 create mode 100644 drivers/gpu/drm/xe/display/xe_display_wa.h

diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.c b/drivers/gpu/drm/i915/display/intel_display_wa.c
index 3662e0f17c69..888676693f5e 100644
--- a/drivers/gpu/drm/i915/display/intel_display_wa.c
+++ b/drivers/gpu/drm/i915/display/intel_display_wa.c
@@ -4,6 +4,7 @@
  */
 
 #include <drm/drm_print.h>
+#include <drm/intel/display_parent_interface.h>
 #include <drm/intel/step.h>
 
 #include "intel_de.h"
@@ -131,7 +132,8 @@ bool __intel_display_wa(struct intel_display *display, enum intel_display_wa wa,
 	case INTEL_DISPLAY_WA_16011863758:
 		return DISPLAY_VER(display) >= 11;
 	case INTEL_DISPLAY_WA_16023588340:
-		return intel_display_needs_wa_16023588340(display);
+		/* This is a GT workaround. */
+		return display->parent->wa && display->parent->wa->wa_16023588340(display->drm);
 	case INTEL_DISPLAY_WA_16025573575:
 		return intel_display_needs_wa_16025573575(display);
 	case INTEL_DISPLAY_WA_16025596647:
diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.h b/drivers/gpu/drm/i915/display/intel_display_wa.h
index 338b32e4162d..425a300840aa 100644
--- a/drivers/gpu/drm/i915/display/intel_display_wa.h
+++ b/drivers/gpu/drm/i915/display/intel_display_wa.h
@@ -12,15 +12,6 @@ struct intel_display;
 
 void intel_display_wa_apply(struct intel_display *display);
 
-#ifdef I915
-static inline bool intel_display_needs_wa_16023588340(struct intel_display *display)
-{
-	return false;
-}
-#else
-bool intel_display_needs_wa_16023588340(struct intel_display *display);
-#endif
-
 /*
  * This enum lists display workarounds; each entry here must have a
  * corresponding case in __intel_display_wa().  Keep both sorted by lineage
diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
index 5f5e79505b3d..0293d316669e 100644
--- a/drivers/gpu/drm/xe/display/xe_display.c
+++ b/drivers/gpu/drm/xe/display/xe_display.c
@@ -37,6 +37,7 @@
 #include "xe_display_bo.h"
 #include "xe_display_pcode.h"
 #include "xe_display_rpm.h"
+#include "xe_display_wa.h"
 #include "xe_dsb_buffer.h"
 #include "xe_fb_pin.h"
 #include "xe_frontbuffer.h"
@@ -472,6 +473,7 @@ static const struct intel_display_parent_interface parent = {
 	.pcode = &xe_display_pcode_interface,
 	.rpm = &xe_display_rpm_interface,
 	.stolen = &xe_display_stolen_interface,
+	.wa = &xe_display_wa_interface,
 	.has_auxccs = has_auxccs,
 	.transient_data_flush = transient_data_flush,
 };
diff --git a/drivers/gpu/drm/xe/display/xe_display_wa.c b/drivers/gpu/drm/xe/display/xe_display_wa.c
index 2aa1b8c03411..46e41e8a3304 100644
--- a/drivers/gpu/drm/xe/display/xe_display_wa.c
+++ b/drivers/gpu/drm/xe/display/xe_display_wa.c
@@ -3,17 +3,22 @@
  * Copyright © 2024 Intel Corporation
  */
 
-#include "intel_display_core.h"
-#include "intel_display_wa.h"
+#include <drm/intel/display_parent_interface.h>
+
 #include "xe_device.h"
+#include "xe_display_wa.h"
 #include "xe_wa.h"
 
 #include <generated/xe_wa_oob.h>
 
-bool intel_display_needs_wa_16023588340(struct intel_display *display)
+static bool intel_display_needs_wa_16023588340(struct drm_device *drm)
 {
-	struct xe_device *xe = to_xe_device(display->drm);
+	struct xe_device *xe = to_xe_device(drm);
 	struct xe_gt *wa_gt = xe_root_mmio_gt(xe);
 
 	return wa_gt && XE_GT_WA(wa_gt, 16023588340);
 }
+
+const struct intel_display_wa_interface xe_display_wa_interface = {
+	.wa_16023588340 = intel_display_needs_wa_16023588340,
+};
diff --git a/drivers/gpu/drm/xe/display/xe_display_wa.h b/drivers/gpu/drm/xe/display/xe_display_wa.h
new file mode 100644
index 000000000000..0262b463916d
--- /dev/null
+++ b/drivers/gpu/drm/xe/display/xe_display_wa.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2026 Intel Corporation */
+
+#ifndef __XE_DISPLAY_WA_H__
+#define __XE_DISPLAY_WA_H__
+
+extern const struct intel_display_wa_interface xe_display_wa_interface;
+
+#endif
diff --git a/include/drm/intel/display_parent_interface.h b/include/drm/intel/display_parent_interface.h
index 8b25107615ea..d7d06dcaa699 100644
--- a/include/drm/intel/display_parent_interface.h
+++ b/include/drm/intel/display_parent_interface.h
@@ -230,6 +230,10 @@ struct intel_display_vlv_iosf_interface {
 	int (*write)(struct drm_device *drm, enum vlv_iosf_sb_unit unit, u32 addr, u32 val);
 };
 
+struct intel_display_wa_interface {
+	bool (*wa_16023588340)(struct drm_device *drm);
+};
+
 /**
  * struct intel_display_parent_interface - services parent driver provides to display
  *
@@ -291,6 +295,12 @@ struct intel_display_parent_interface {
 	/** @vlv_iosf: VLV IOSF sideband. Optional. */
 	const struct intel_display_vlv_iosf_interface *vlv_iosf;
 
+	/**
+	 * @wa: Display workarounds query. Use only for workarounds that require
+	 * information only available to the parent driver. Optional.
+	 */
+	const struct intel_display_wa_interface *wa;
+
 	/* Generic independent functions */
 	struct {
 		/** @fence_priority_display: Set display priority. Optional. */
-- 
2.47.3