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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include "gem/i915_gem_pm.h"
#include "gt/intel_gt.h"
#include "gt/intel_gt_pm.h"
#include "gt/intel_gt_requests.h"
#include "i915_drv.h"
static bool switch_to_kernel_context_sync(struct intel_gt *gt)
{
bool result = !intel_gt_is_wedged(gt);
if (intel_gt_wait_for_idle(gt, I915_GEM_IDLE_TIMEOUT) == -ETIME) {
/* XXX hide warning from gem_eio */
if (i915_modparams.reset) {
dev_err(gt->i915->drm.dev,
"Failed to idle engines, declaring wedged!\n");
GEM_TRACE_DUMP();
}
/*
* Forcibly cancel outstanding work and leave
* the gpu quiet.
*/
intel_gt_set_wedged(gt);
result = false;
}
if (intel_gt_pm_wait_for_idle(gt))
result = false;
return result;
}
static void user_forcewake(struct intel_gt *gt, bool suspend)
{
int count = atomic_read(>->user_wakeref);
/* Inside suspend/resume so single threaded, no races to worry about. */
if (likely(!count))
return;
intel_gt_pm_get(gt);
if (suspend) {
GEM_BUG_ON(count > atomic_read(>->wakeref.count));
atomic_sub(count, >->wakeref.count);
} else {
atomic_add(count, >->wakeref.count);
}
intel_gt_pm_put(gt);
}
void i915_gem_suspend(struct drm_i915_private *i915)
{
GEM_TRACE("\n");
intel_wakeref_auto(&i915->ggtt.userfault_wakeref, 0);
flush_workqueue(i915->wq);
user_forcewake(&i915->gt, true);
/*
* We have to flush all the executing contexts to main memory so
* that they can saved in the hibernation image. To ensure the last
* context image is coherent, we have to switch away from it. That
* leaves the i915->kernel_context still active when
* we actually suspend, and its image in memory may not match the GPU
* state. Fortunately, the kernel_context is disposable and we do
* not rely on its state.
*/
intel_gt_suspend(&i915->gt);
i915_gem_drain_freed_objects(i915);
}
static struct drm_i915_gem_object *first_mm_object(struct list_head *list)
{
return list_first_entry_or_null(list,
struct drm_i915_gem_object,
mm.link);
}
void i915_gem_suspend_late(struct drm_i915_private *i915)
{
struct drm_i915_gem_object *obj;
struct list_head *phases[] = {
&i915->mm.shrink_list,
&i915->mm.purge_list,
NULL
}, **phase;
unsigned long flags;
/*
* Neither the BIOS, ourselves or any other kernel
* expects the system to be in execlists mode on startup,
* so we need to reset the GPU back to legacy mode. And the only
* known way to disable logical contexts is through a GPU reset.
*
* So in order to leave the system in a known default configuration,
* always reset the GPU upon unload and suspend. Afterwards we then
* clean up the GEM state tracking, flushing off the requests and
* leaving the system in a known idle state.
*
* Note that is of the upmost importance that the GPU is idle and
* all stray writes are flushed *before* we dismantle the backing
* storage for the pinned objects.
*
* However, since we are uncertain that resetting the GPU on older
* machines is a good idea, we don't - just in case it leaves the
* machine in an unusable condition.
*/
spin_lock_irqsave(&i915->mm.obj_lock, flags);
for (phase = phases; *phase; phase++) {
LIST_HEAD(keep);
while ((obj = first_mm_object(*phase))) {
list_move_tail(&obj->mm.link, &keep);
/* Beware the background _i915_gem_free_objects */
if (!kref_get_unless_zero(&obj->base.refcount))
continue;
spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
i915_gem_object_lock(obj);
WARN_ON(i915_gem_object_set_to_gtt_domain(obj, false));
i915_gem_object_unlock(obj);
i915_gem_object_put(obj);
spin_lock_irqsave(&i915->mm.obj_lock, flags);
}
list_splice_tail(&keep, *phase);
}
spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
}
void i915_gem_resume(struct drm_i915_private *i915)
{
GEM_TRACE("\n");
intel_uncore_forcewake_get(&i915->uncore, FORCEWAKE_ALL);
if (intel_gt_init_hw(&i915->gt))
goto err_wedged;
/*
* As we didn't flush the kernel context before suspend, we cannot
* guarantee that the context image is complete. So let's just reset
* it and start again.
*/
if (intel_gt_resume(&i915->gt))
goto err_wedged;
/* Always reload a context for powersaving. */
if (!switch_to_kernel_context_sync(&i915->gt))
goto err_wedged;
user_forcewake(&i915->gt, false);
out_unlock:
intel_uncore_forcewake_put(&i915->uncore, FORCEWAKE_ALL);
return;
err_wedged:
if (!intel_gt_is_wedged(&i915->gt)) {
dev_err(i915->drm.dev,
"Failed to re-initialize GPU, declaring it wedged!\n");
intel_gt_set_wedged(&i915->gt);
}
goto out_unlock;
}
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