Commit 3afef438 authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/i915/frontbuffer: Split fb_tracking.lock into two 



Our fb_tracking.lock is serving a double duty:
- protects fb_tracking.busy_bits
- provides the write-side protection for obj->frontbuffer

Split obj->frontbuffer role into a separate lock so that
we can clean up the current mess with the frontbuffer lifetime
management.

Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20251016185408.22735-7-ville.syrjala@linux.intel.com


Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
parent 65417489

drivers/gpu/drm/i915/display/intel_display_core.h

+4 −0
Original line number Diff line number Diff line
@@ -142,6 +142,10 @@ struct intel_dpll_global { 
};



struct intel_frontbuffer_tracking {

	/* protects obj->frontbuffer (write-side) */

	spinlock_t frontbuffer_lock;



	/* protects busy_bits */

	spinlock_t lock;



	/*

drivers/gpu/drm/i915/display/intel_display_driver.c

+1 −0
Original line number Diff line number Diff line
@@ -186,6 +186,7 @@ void intel_display_driver_early_probe(struct intel_display *display) 
	if (!HAS_DISPLAY(display))

		return;



	spin_lock_init(&display->fb_tracking.frontbuffer_lock);

	spin_lock_init(&display->fb_tracking.lock);

	mutex_init(&display->backlight.lock);

	mutex_init(&display->audio.mutex);

drivers/gpu/drm/i915/display/intel_frontbuffer.c

+5 −5
Original line number Diff line number Diff line
@@ -210,7 +210,7 @@ static void frontbuffer_retire(struct i915_active *ref) 
}



static void frontbuffer_release(struct kref *ref)

	__releases(&to_intel_display(front->obj->dev)->fb_tracking.lock)

	__releases(&to_intel_display(front->obj->dev)->fb_tracking.frontbuffer_lock)

{

	struct intel_frontbuffer *ret, *front =

		container_of(ref, typeof(*front), ref);
@@ -223,7 +223,7 @@ static void frontbuffer_release(struct kref *ref) 


	ret = intel_bo_set_frontbuffer(obj, NULL);

	drm_WARN_ON(display->drm, ret);

	spin_unlock(&display->fb_tracking.lock);

	spin_unlock(&display->fb_tracking.frontbuffer_lock);



	i915_active_fini(&front->write);
@@ -256,9 +256,9 @@ intel_frontbuffer_get(struct drm_gem_object *obj) 
			 I915_ACTIVE_RETIRE_SLEEPS);

	INIT_WORK(&front->flush_work, intel_frontbuffer_flush_work);



	spin_lock(&display->fb_tracking.lock);

	spin_lock(&display->fb_tracking.frontbuffer_lock);

	cur = intel_bo_set_frontbuffer(obj, front);

	spin_unlock(&display->fb_tracking.lock);

	spin_unlock(&display->fb_tracking.frontbuffer_lock);



	if (cur != front) {

		drm_gem_object_put(obj);
@@ -272,7 +272,7 @@ void intel_frontbuffer_put(struct intel_frontbuffer *front) 
{

	kref_put_lock(&front->ref,

		      frontbuffer_release,

		      &to_intel_display(front->obj->dev)->fb_tracking.lock);

		      &to_intel_display(front->obj->dev)->fb_tracking.frontbuffer_lock);

}



/**

drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.h

+1 −1
Original line number Diff line number Diff line
@@ -77,7 +77,7 @@ i915_gem_object_get_frontbuffer(const struct drm_i915_gem_object *obj) 
 * Set object's frontbuffer pointer. If frontbuffer is already set for the

 * object keep it and return it's pointer to the caller. Please note that RCU

 * mechanism is used to handle e.g. ongoing removal of frontbuffer pointer. This

 * function is protected by i915->display->fb_tracking.lock

 * function is protected by i915->display->fb_tracking.frontbuffer_lock

 *

 * Return: pointer to frontbuffer which was set.

 */