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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include "i915_drv.h"
#include "intel_engine.h"
#include "intel_engine_pm.h"
#include "intel_gt.h"
#include "intel_gt_pm.h"
static int __engine_unpark(struct intel_wakeref *wf)
{
struct intel_engine_cs *engine =
container_of(wf, typeof(*engine), wakeref);
void *map;
GEM_TRACE("%s\n", engine->name);
intel_gt_pm_get(engine->gt);
/* Pin the default state for fast resets from atomic context. */
map = NULL;
if (engine->default_state)
map = i915_gem_object_pin_map(engine->default_state,
I915_MAP_WB);
if (!IS_ERR_OR_NULL(map))
engine->pinned_default_state = map;
if (engine->unpark)
engine->unpark(engine);
intel_engine_init_hangcheck(engine);
return 0;
}
void intel_engine_pm_get(struct intel_engine_cs *engine)
{
intel_wakeref_get(&engine->i915->runtime_pm, &engine->wakeref, __engine_unpark);
}
void intel_engine_park(struct intel_engine_cs *engine)
{
/*
* We are committed now to parking this engine, make sure there
* will be no more interrupts arriving later and the engine
* is truly idle.
*/
if (wait_for(intel_engine_is_idle(engine), 10)) {
struct drm_printer p = drm_debug_printer(__func__);
dev_err(engine->i915->drm.dev,
"%s is not idle before parking\n",
engine->name);
intel_engine_dump(engine, &p, NULL);
}
}
static bool switch_to_kernel_context(struct intel_engine_cs *engine)
{
struct i915_request *rq;
/* Already inside the kernel context, safe to power down. */
if (engine->wakeref_serial == engine->serial)
return true;
/* GPU is pointing to the void, as good as in the kernel context. */
if (intel_gt_is_wedged(engine->gt))
return true;
/*
* Note, we do this without taking the timeline->mutex. We cannot
* as we may be called while retiring the kernel context and so
* already underneath the timeline->mutex. Instead we rely on the
* exclusive property of the __engine_park that prevents anyone
* else from creating a request on this engine. This also requires
* that the ring is empty and we avoid any waits while constructing
* the context, as they assume protection by the timeline->mutex.
* This should hold true as we can only park the engine after
* retiring the last request, thus all rings should be empty and
* all timelines idle.
*/
rq = __i915_request_create(engine->kernel_context, GFP_NOWAIT);
if (IS_ERR(rq))
/* Context switch failed, hope for the best! Maybe reset? */
return true;
/* Check again on the next retirement. */
engine->wakeref_serial = engine->serial + 1;
i915_request_add_barriers(rq);
__i915_request_commit(rq);
return false;
}
static int __engine_park(struct intel_wakeref *wf)
{
struct intel_engine_cs *engine =
container_of(wf, typeof(*engine), wakeref);
engine->saturated = 0;
/*
* If one and only one request is completed between pm events,
* we know that we are inside the kernel context and it is
* safe to power down. (We are paranoid in case that runtime
* suspend causes corruption to the active context image, and
* want to avoid that impacting userspace.)
*/
if (!switch_to_kernel_context(engine))
return -EBUSY;
GEM_TRACE("%s\n", engine->name);
intel_engine_disarm_breadcrumbs(engine);
/* Must be reset upon idling, or we may miss the busy wakeup. */
GEM_BUG_ON(engine->execlists.queue_priority_hint != INT_MIN);
if (engine->park)
engine->park(engine);
if (engine->pinned_default_state) {
i915_gem_object_unpin_map(engine->default_state);
engine->pinned_default_state = NULL;
}
engine->execlists.no_priolist = false;
intel_gt_pm_put(engine->gt);
return 0;
}
void intel_engine_pm_put(struct intel_engine_cs *engine)
{
intel_wakeref_put(&engine->i915->runtime_pm, &engine->wakeref, __engine_park);
}
void intel_engine_init__pm(struct intel_engine_cs *engine)
{
intel_wakeref_init(&engine->wakeref);
}
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