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Commit 67e64564 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Provide an assert for when we expect forcewake to be held 



Add assert_forcewakes_active() (the complementary function to
assert_forcewakes_inactive) that documents the requirement of a
function for its callers to be holding the forcewake ref (i.e. the
function is part of a sequence over which RC6 must be prevented).

One such example is during ringbuffer reset, where RC6 must be held
across the whole reinitialisation sequence.

v2: Include debug information in the WARN so we know which fw domain is
missing.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20171009110301.21705-5-chris@chris-wilson.co.uk
parent ff97d3ae

drivers/gpu/drm/i915/intel_ringbuffer.c

+10 −1
Original line number Original line Diff line number Diff line
@@ -579,7 +579,16 @@ static int init_ring_common(struct intel_engine_cs *engine) 
static void reset_ring_common(struct intel_engine_cs *engine,

static void reset_ring_common(struct intel_engine_cs *engine,

			      struct drm_i915_gem_request *request)

			      struct drm_i915_gem_request *request)

{

{

	/* Try to restore the logical GPU state to match the continuation

	/*

	 * RC6 must be prevented until the reset is complete and the engine

	 * reinitialised. If it occurs in the middle of this sequence, the

	 * state written to/loaded from the power context is ill-defined (e.g.

	 * the PP_BASE_DIR may be lost).

	 */

	assert_forcewakes_active(engine->i915, FORCEWAKE_ALL);



	/*

	 * Try to restore the logical GPU state to match the continuation

	 * of the request queue. If we skip the context/PD restore, then

	 * of the request queue. If we skip the context/PD restore, then

	 * the next request may try to execute assuming that its context

	 * the next request may try to execute assuming that its context

	 * is valid and loaded on the GPU and so may try to access invalid

	 * is valid and loaded on the GPU and so may try to access invalid

drivers/gpu/drm/i915/intel_uncore.c

+17 −1
Original line number Original line Diff line number Diff line
@@ -626,7 +626,23 @@ void assert_forcewakes_inactive(struct drm_i915_private *dev_priv) 
	if (!dev_priv->uncore.funcs.force_wake_get)

	if (!dev_priv->uncore.funcs.force_wake_get)

		return;

		return;





	WARN_ON(dev_priv->uncore.fw_domains_active);

	WARN(dev_priv->uncore.fw_domains_active,

	     "Expected all fw_domains to be inactive, but %08x are still on\n",

	     dev_priv->uncore.fw_domains_active);

}



void assert_forcewakes_active(struct drm_i915_private *dev_priv,

			      enum forcewake_domains fw_domains)

{

	if (!dev_priv->uncore.funcs.force_wake_get)

		return;



	assert_rpm_wakelock_held(dev_priv);



	fw_domains &= dev_priv->uncore.fw_domains;

	WARN(fw_domains & ~dev_priv->uncore.fw_domains_active,

	     "Expected %08x fw_domains to be active, but %08x are off\n",

	     fw_domains, fw_domains & ~dev_priv->uncore.fw_domains_active);

}

}





/* We give fast paths for the really cool registers */

/* We give fast paths for the really cool registers */

drivers/gpu/drm/i915/intel_uncore.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -137,6 +137,8 @@ void intel_uncore_resume_early(struct drm_i915_private *dev_priv); 




u64 intel_uncore_edram_size(struct drm_i915_private *dev_priv);

u64 intel_uncore_edram_size(struct drm_i915_private *dev_priv);

void assert_forcewakes_inactive(struct drm_i915_private *dev_priv);

void assert_forcewakes_inactive(struct drm_i915_private *dev_priv);

void assert_forcewakes_active(struct drm_i915_private *dev_priv,

			      enum forcewake_domains fw_domains);

const char *intel_uncore_forcewake_domain_to_str(const enum forcewake_domain_id id);

const char *intel_uncore_forcewake_domain_to_str(const enum forcewake_domain_id id);





enum forcewake_domains

enum forcewake_domains