Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/i915/pc8: Add parent interface for PC8 forcewake tricks
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.
v2: Mark the interface optional and warn if
someone calls it when not provided (Jani)
Include the header to make sure the extern
declaration matches the definition (Jani)
v3: Rebase due to shuffling
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20251218182052.18756-1-ville.syrjala@linux.intel.com
+76
-4
+1
drivers/gpu/drm/i915/Makefile
+1
drivers/gpu/drm/i915/Makefile
+4
-4
drivers/gpu/drm/i915/display/intel_display_power.c
+4
-4
drivers/gpu/drm/i915/display/intel_display_power.c
···
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return;
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/*
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-
* Make sure we're not on PC8 state before disabling PC8, otherwise
1343
-
* we'll hang the machine. To prevent PC8 state, just enable force_wake.
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+
* Make sure we're not on PC8 state before disabling
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* PC8, otherwise we'll hang the machine.
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*/
1345
-
intel_uncore_forcewake_get(&dev_priv->uncore, FORCEWAKE_ALL);
1345
+
intel_parent_pc8_block(display);
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if (val & LCPLL_POWER_DOWN_ALLOW) {
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val &= ~LCPLL_POWER_DOWN_ALLOW;
···
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"Switching back to LCPLL failed\n");
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}
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-
intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);
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+
intel_parent_pc8_unblock(display);
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intel_update_cdclk(display);
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intel_cdclk_dump_config(display, &display->cdclk.hw, "Current CDCLK");
+17
drivers/gpu/drm/i915/display/intel_parent.c
+17
drivers/gpu/drm/i915/display/intel_parent.c
···
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display->parent->panic->finish(panic);
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}
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+
/* pc8 */
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void intel_parent_pc8_block(struct intel_display *display)
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+
{
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if (drm_WARN_ON_ONCE(display->drm, !display->parent->pc8))
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+
return;
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+
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display->parent->pc8->block(display->drm);
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+
}
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+
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void intel_parent_pc8_unblock(struct intel_display *display)
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{
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if (drm_WARN_ON_ONCE(display->drm, !display->parent->pc8))
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return;
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+
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display->parent->pc8->unblock(display->drm);
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+
}
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+
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/* rps */
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bool intel_parent_rps_available(struct intel_display *display)
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{
+4
drivers/gpu/drm/i915/display/intel_parent.h
+4
drivers/gpu/drm/i915/display/intel_parent.h
···
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int intel_parent_panic_setup(struct intel_display *display, struct intel_panic *panic, struct drm_scanout_buffer *sb);
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void intel_parent_panic_finish(struct intel_display *display, struct intel_panic *panic);
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+
/* pc8 */
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void intel_parent_pc8_block(struct intel_display *display);
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void intel_parent_pc8_unblock(struct intel_display *display);
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+
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/* rps */
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bool intel_parent_rps_available(struct intel_display *display);
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void intel_parent_rps_boost_if_not_started(struct intel_display *display, struct dma_fence *fence);
+31
drivers/gpu/drm/i915/i915_display_pc8.c
+31
drivers/gpu/drm/i915/i915_display_pc8.c
···
1
+
// SPDX-License-Identifier: MIT
2
+
/*
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+
* Copyright 2025, Intel Corporation.
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+
*/
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+
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#include <drm/drm_print.h>
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#include <drm/intel/display_parent_interface.h>
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+
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#include "i915_display_pc8.h"
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#include "i915_drv.h"
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#include "intel_uncore.h"
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+
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static void i915_display_pc8_block(struct drm_device *drm)
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+
{
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struct intel_uncore *uncore = &to_i915(drm)->uncore;
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+
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/* to prevent PC8 state, just enable force_wake */
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intel_uncore_forcewake_get(uncore, FORCEWAKE_ALL);
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+
}
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+
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static void i915_display_pc8_unblock(struct drm_device *drm)
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+
{
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struct intel_uncore *uncore = &to_i915(drm)->uncore;
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+
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intel_uncore_forcewake_put(uncore, FORCEWAKE_ALL);
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+
}
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+
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const struct intel_display_pc8_interface i915_display_pc8_interface = {
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.block = i915_display_pc8_block,
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+
.unblock = i915_display_pc8_unblock,
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+
};
+9
drivers/gpu/drm/i915/i915_display_pc8.h
+9
drivers/gpu/drm/i915/i915_display_pc8.h
+2
drivers/gpu/drm/i915/i915_driver.c
+2
drivers/gpu/drm/i915/i915_driver.c
···
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#include "pxp/intel_pxp_pm.h"
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#include "i915_debugfs.h"
92
+
#include "i915_display_pc8.h"
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#include "i915_driver.h"
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#include "i915_drm_client.h"
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#include "i915_drv.h"
···
766
765
.hdcp = &i915_display_hdcp_interface,
767
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.irq = &i915_display_irq_interface,
768
767
.panic = &i915_display_panic_interface,
768
+
.pc8 = &i915_display_pc8_interface,
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.rpm = &i915_display_rpm_interface,
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.rps = &i915_display_rps_interface,
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.stolen = &i915_display_stolen_interface,
+8
include/drm/intel/display_parent_interface.h
+8
include/drm/intel/display_parent_interface.h
···
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void (*finish)(struct intel_panic *panic);
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};
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+
struct intel_display_pc8_interface {
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void (*block)(struct drm_device *drm);
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+
void (*unblock)(struct drm_device *drm);
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+
};
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+
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struct intel_display_rpm_interface {
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struct ref_tracker *(*get)(const struct drm_device *drm);
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struct ref_tracker *(*get_raw)(const struct drm_device *drm);
···
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/** @panic: Panic interface */
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const struct intel_display_panic_interface *panic;
98
+
99
+
/** @pc8: PC8 interface. Optional. */
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+
const struct intel_display_pc8_interface *pc8;
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/** @rpm: Runtime PM functions */
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const struct intel_display_rpm_interface *rpm;