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* [PATCH] drm/i915/pc8: Add parent interface for PC8 forcewake tricks
@ 2025-12-09 11:11 Ville Syrjala
  2025-12-09 11:17 ` ✗ CI.checkpatch: warning for " Patchwork
                   ` (11 more replies)
  0 siblings, 12 replies; 16+ messages in thread
From: Ville Syrjala @ 2025-12-09 11:11 UTC (permalink / raw)
  To: intel-gfx; +Cc: intel-xe

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

We use forcewake to prevent the SoC from actually entering
PC8 while performing the PC8 disable sequence. Hide that
behind a new parent interface to eliminate the naked
forcewake/uncore usage from the display power code.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/Makefile                 |  1 +
 .../drm/i915/display/intel_display_power.c    |  8 ++---
 drivers/gpu/drm/i915/display/intel_parent.c   | 10 +++++++
 drivers/gpu/drm/i915/display/intel_parent.h   |  3 ++
 drivers/gpu/drm/i915/i915_display_pc8.c       | 30 +++++++++++++++++++
 drivers/gpu/drm/i915/i915_display_pc8.h       |  9 ++++++
 drivers/gpu/drm/i915/i915_driver.c            |  2 ++
 include/drm/intel/display_parent_interface.h  |  8 +++++
 8 files changed, 67 insertions(+), 4 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/i915_display_pc8.c
 create mode 100644 drivers/gpu/drm/i915/i915_display_pc8.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 175bd99e1d0d..b57e51d626b1 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -76,6 +76,7 @@ i915-$(CONFIG_PERF_EVENTS) += \
 
 # core display adaptation
 i915-y += \
+	i915_display_pc8.o \
 	i915_hdcp_gsc.o
 
 # "Graphics Technology" (aka we talk to the gpu)
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 9f323c39d798..47042a4c3a30 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -1339,10 +1339,10 @@ static void hsw_restore_lcpll(struct intel_display *display)
 		return;
 
 	/*
-	 * Make sure we're not on PC8 state before disabling PC8, otherwise
-	 * we'll hang the machine. To prevent PC8 state, just enable force_wake.
+	 * Make sure we're not on PC8 state before disabling
+	 * PC8, otherwise we'll hang the machine.
 	 */
-	intel_uncore_forcewake_get(&dev_priv->uncore, FORCEWAKE_ALL);
+	intel_parent_pc8_block(display);
 
 	if (val & LCPLL_POWER_DOWN_ALLOW) {
 		val &= ~LCPLL_POWER_DOWN_ALLOW;
@@ -1372,7 +1372,7 @@ static void hsw_restore_lcpll(struct intel_display *display)
 				"Switching back to LCPLL failed\n");
 	}
 
-	intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);
+	intel_parent_pc8_unblock(display);
 
 	intel_update_cdclk(display);
 	intel_cdclk_dump_config(display, &display->cdclk.hw, "Current CDCLK");
diff --git a/drivers/gpu/drm/i915/display/intel_parent.c b/drivers/gpu/drm/i915/display/intel_parent.c
index 2ea310cc3509..9201d506c851 100644
--- a/drivers/gpu/drm/i915/display/intel_parent.c
+++ b/drivers/gpu/drm/i915/display/intel_parent.c
@@ -56,6 +56,16 @@ void intel_parent_irq_synchronize(struct intel_display *display)
 	display->parent->irq->synchronize(display->drm);
 }
 
+void intel_parent_pc8_block(struct intel_display *display)
+{
+	display->parent->pc8->block(display->drm);
+}
+
+void intel_parent_pc8_unblock(struct intel_display *display)
+{
+	display->parent->pc8->unblock(display->drm);
+}
+
 bool intel_parent_rps_available(struct intel_display *display)
 {
 	return display->parent->rps;
diff --git a/drivers/gpu/drm/i915/display/intel_parent.h b/drivers/gpu/drm/i915/display/intel_parent.h
index 8f91a6f75c53..974a016ab3be 100644
--- a/drivers/gpu/drm/i915/display/intel_parent.h
+++ b/drivers/gpu/drm/i915/display/intel_parent.h
@@ -22,6 +22,9 @@ void intel_parent_hdcp_gsc_context_free(struct intel_display *display,
 bool intel_parent_irq_enabled(struct intel_display *display);
 void intel_parent_irq_synchronize(struct intel_display *display);
 
+void intel_parent_pc8_block(struct intel_display *display);
+void intel_parent_pc8_unblock(struct intel_display *display);
+
 bool intel_parent_rps_available(struct intel_display *display);
 void intel_parent_rps_boost_if_not_started(struct intel_display *display, struct dma_fence *fence);
 void intel_parent_rps_mark_interactive(struct intel_display *display, bool interactive);
diff --git a/drivers/gpu/drm/i915/i915_display_pc8.c b/drivers/gpu/drm/i915/i915_display_pc8.c
new file mode 100644
index 000000000000..443935d282e3
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_display_pc8.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2025, Intel Corporation.
+ */
+
+#include <drm/drm_print.h>
+#include <drm/intel/display_parent_interface.h>
+
+#include "i915_drv.h"
+#include "intel_uncore.h"
+
+static void i915_display_pc8_block(struct drm_device *drm)
+{
+	struct intel_uncore *uncore = &to_i915(drm)->uncore;
+
+	/* to prevent PC8 state, just enable force_wake */
+	intel_uncore_forcewake_get(uncore, FORCEWAKE_ALL);
+}
+
+static void i915_display_pc8_unblock(struct drm_device *drm)
+{
+	struct intel_uncore *uncore = &to_i915(drm)->uncore;
+
+	intel_uncore_forcewake_put(uncore, FORCEWAKE_ALL);
+}
+
+const struct intel_display_pc8_interface i915_display_pc8_interface = {
+	.block = i915_display_pc8_block,
+	.unblock = i915_display_pc8_unblock,
+};
diff --git a/drivers/gpu/drm/i915/i915_display_pc8.h b/drivers/gpu/drm/i915/i915_display_pc8.h
new file mode 100644
index 000000000000..717f313d2a21
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_display_pc8.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2025 Intel Corporation */
+
+#ifndef __I915_DISPLAY_PC8_H__
+#define __I915_DISPLAY_PC8_H__
+
+extern const struct intel_display_pc8_interface i915_display_pc8_interface;
+
+#endif /* __I915_DISPLAY_PC8_H__ */
diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index d98839427ef9..723cb424b2ba 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -89,6 +89,7 @@
 #include "pxp/intel_pxp_pm.h"
 
 #include "i915_debugfs.h"
+#include "i915_display_pc8.h"
 #include "i915_driver.h"
 #include "i915_drm_client.h"
 #include "i915_drv.h"
@@ -761,6 +762,7 @@ static const struct intel_display_parent_interface parent = {
 	.hdcp = &i915_display_hdcp_interface,
 	.rpm = &i915_display_rpm_interface,
 	.irq = &i915_display_irq_interface,
+	.pc8 = &i915_display_pc8_interface,
 	.rps = &i915_display_rps_interface,
 	.vgpu_active = vgpu_active,
 	.has_fenced_regions = has_fenced_regions,
diff --git a/include/drm/intel/display_parent_interface.h b/include/drm/intel/display_parent_interface.h
index 61d1b22adc83..af43b213eafa 100644
--- a/include/drm/intel/display_parent_interface.h
+++ b/include/drm/intel/display_parent_interface.h
@@ -41,6 +41,11 @@ struct intel_display_irq_interface {
 	void (*synchronize)(struct drm_device *drm);
 };
 
+struct intel_display_pc8_interface {
+	void (*block)(struct drm_device *drm);
+	void (*unblock)(struct drm_device *drm);
+};
+
 struct intel_display_rps_interface {
 	void (*boost_if_not_started)(struct dma_fence *fence);
 	void (*mark_interactive)(struct drm_device *drm, bool interactive);
@@ -69,6 +74,9 @@ struct intel_display_parent_interface {
 	/** @irq: IRQ interface */
 	const struct intel_display_irq_interface *irq;
 
+	/** @pc8: PC8 interface */
+	const struct intel_display_pc8_interface *pc8;
+
 	/** @rpm: RPS interface. Optional. */
 	const struct intel_display_rps_interface *rps;
 
-- 
2.51.2


^ permalink raw reply related	[flat|nested] 16+ messages in thread
end of thread, other threads:[~2025-12-19 18:33 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-12-09 11:11 [PATCH] drm/i915/pc8: Add parent interface for PC8 forcewake tricks Ville Syrjala
2025-12-09 11:17 ` ✗ CI.checkpatch: warning for " Patchwork
2025-12-09 11:18 ` ✓ CI.KUnit: success " Patchwork
2025-12-09 11:33 ` ✗ CI.checksparse: warning " Patchwork
2025-12-09 12:13 ` [PATCH] " Jani Nikula
2025-12-09 12:23   ` Jani Nikula
2025-12-09 19:59   ` Ville Syrjälä
2025-12-09 12:24 ` ✓ Xe.CI.BAT: success for " Patchwork
2025-12-09 17:39 ` ✗ Xe.CI.Full: failure " Patchwork
2025-12-10 17:26 ` [PATCH v2] " Ville Syrjala
2025-12-11  8:42   ` Jani Nikula
2025-12-18 18:20 ` [PATCH v3] " Ville Syrjala
2025-12-18 19:33 ` ✗ CI.checkpatch: warning for drm/i915/pc8: Add parent interface for PC8 forcewake tricks (rev3) Patchwork
2025-12-18 19:34 ` ✓ CI.KUnit: success " Patchwork
2025-12-18 20:24 ` ✓ Xe.CI.BAT: " Patchwork
2025-12-19 18:33 ` ✓ Xe.CI.Full: " Patchwork

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