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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"
#if defined(CONFIG_X86)
#include <asm/smp.h>
#else
#define wbinvd_on_all_cpus() \
pr_warn(DRIVER_NAME ": Missing cache flush in %s\n", __func__)
#endif
void i915_gem_suspend(struct drm_i915_private *i915)
{
GEM_TRACE("%s\n", dev_name(i915->drm.dev));
intel_wakeref_auto(&i915->ggtt.userfault_wakeref, 0);
flush_workqueue(i915->wq);
/*
* 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_prepare(&i915->gt);
i915_gem_drain_freed_objects(i915);
}
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;
bool flush = false;
/*
* 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.
*/
intel_gt_suspend_late(&i915->gt);
spin_lock_irqsave(&i915->mm.obj_lock, flags);
for (phase = phases; *phase; phase++) {
list_for_each_entry(obj, *phase, mm.link) {
if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ))
flush |= (obj->read_domains & I915_GEM_DOMAIN_CPU) == 0;
__start_cpu_write(obj); /* presume auto-hibernate */
}
}
spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
if (flush)
wbinvd_on_all_cpus();
}
void i915_gem_resume(struct drm_i915_private *i915)
{
GEM_TRACE("%s\n", dev_name(i915->drm.dev));
/*
* 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.
*/
intel_gt_resume(&i915->gt);
}
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