From: Ville Syrjälä Date: Thu, 18 Dec 2025 18:20:52 +0000 (+0200) Subject: drm/i915/pc8: Add parent interface for PC8 forcewake tricks X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=35ec71285c9311395b14bedc60fa94f6b7e24d2d;p=thirdparty%2Fkernel%2Flinux.git 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 Signed-off-by: Ville Syrjälä Link: https://patch.msgid.link/20251218182052.18756-1-ville.syrjala@linux.intel.com --- diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index 13b9e71fa993..801dd155d1f0 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 \ i915_panic.o 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 9b1a84a439e9..72ae553f79a4 100644 --- a/drivers/gpu/drm/i915/display/intel_parent.c +++ b/drivers/gpu/drm/i915/display/intel_parent.c @@ -75,6 +75,23 @@ void intel_parent_panic_finish(struct intel_display *display, struct intel_panic display->parent->panic->finish(panic); } +/* pc8 */ +void intel_parent_pc8_block(struct intel_display *display) +{ + if (drm_WARN_ON_ONCE(display->drm, !display->parent->pc8)) + return; + + display->parent->pc8->block(display->drm); +} + +void intel_parent_pc8_unblock(struct intel_display *display) +{ + if (drm_WARN_ON_ONCE(display->drm, !display->parent->pc8)) + return; + + display->parent->pc8->unblock(display->drm); +} + /* rps */ bool intel_parent_rps_available(struct intel_display *display) { diff --git a/drivers/gpu/drm/i915/display/intel_parent.h b/drivers/gpu/drm/i915/display/intel_parent.h index a2a631fba118..47cdc14f9aa2 100644 --- a/drivers/gpu/drm/i915/display/intel_parent.h +++ b/drivers/gpu/drm/i915/display/intel_parent.h @@ -32,6 +32,10 @@ struct intel_panic *intel_parent_panic_alloc(struct intel_display *display); int intel_parent_panic_setup(struct intel_display *display, struct intel_panic *panic, struct drm_scanout_buffer *sb); void intel_parent_panic_finish(struct intel_display *display, struct intel_panic *panic); +/* pc8 */ +void intel_parent_pc8_block(struct intel_display *display); +void intel_parent_pc8_unblock(struct intel_display *display); + /* rps */ 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); 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..2af5dbab20ef --- /dev/null +++ b/drivers/gpu/drm/i915/i915_display_pc8.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright 2025, Intel Corporation. + */ + +#include +#include + +#include "i915_display_pc8.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 75f503e52e70..e025273e9ab1 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" @@ -765,6 +766,7 @@ static const struct intel_display_parent_interface parent = { .hdcp = &i915_display_hdcp_interface, .irq = &i915_display_irq_interface, .panic = &i915_display_panic_interface, + .pc8 = &i915_display_pc8_interface, .rpm = &i915_display_rpm_interface, .rps = &i915_display_rps_interface, .stolen = &i915_display_stolen_interface, diff --git a/include/drm/intel/display_parent_interface.h b/include/drm/intel/display_parent_interface.h index 55d4df714645..10c50b42844e 100644 --- a/include/drm/intel/display_parent_interface.h +++ b/include/drm/intel/display_parent_interface.h @@ -36,6 +36,11 @@ struct intel_display_panic_interface { void (*finish)(struct intel_panic *panic); }; +struct intel_display_pc8_interface { + void (*block)(struct drm_device *drm); + void (*unblock)(struct drm_device *drm); +}; + struct intel_display_rpm_interface { struct ref_tracker *(*get)(const struct drm_device *drm); struct ref_tracker *(*get_raw)(const struct drm_device *drm); @@ -96,6 +101,9 @@ struct intel_display_parent_interface { /** @panic: Panic interface */ const struct intel_display_panic_interface *panic; + /** @pc8: PC8 interface. Optional. */ + const struct intel_display_pc8_interface *pc8; + /** @rpm: Runtime PM functions */ const struct intel_display_rpm_interface *rpm;