1 /*
2 * SPDX-License-Identifier: MIT
3 *
4 * Copyright © 2019 Intel Corporation
5 */
6
7 #include "gem/i915_gem_pm.h"
8 #include "gt/intel_gt.h"
9 #include "gt/intel_gt_pm.h"
10 #include "gt/intel_gt_requests.h"
11
12 #include "i915_drv.h"
13
i915_gem_suspend(struct drm_i915_private * i915)14 void i915_gem_suspend(struct drm_i915_private *i915)
15 {
16 GEM_TRACE("%s\n", dev_name(i915->drm.dev));
17
18 intel_wakeref_auto(&i915->ggtt.userfault_wakeref, 0);
19 flush_workqueue(i915->wq);
20
21 /*
22 * We have to flush all the executing contexts to main memory so
23 * that they can saved in the hibernation image. To ensure the last
24 * context image is coherent, we have to switch away from it. That
25 * leaves the i915->kernel_context still active when
26 * we actually suspend, and its image in memory may not match the GPU
27 * state. Fortunately, the kernel_context is disposable and we do
28 * not rely on its state.
29 */
30 intel_gt_suspend_prepare(&i915->gt);
31
32 i915_gem_drain_freed_objects(i915);
33 }
34
first_mm_object(struct list_head * list)35 static struct drm_i915_gem_object *first_mm_object(struct list_head *list)
36 {
37 return list_first_entry_or_null(list,
38 struct drm_i915_gem_object,
39 mm.link);
40 }
41
i915_gem_suspend_late(struct drm_i915_private * i915)42 void i915_gem_suspend_late(struct drm_i915_private *i915)
43 {
44 struct drm_i915_gem_object *obj;
45 struct list_head *phases[] = {
46 &i915->mm.shrink_list,
47 &i915->mm.purge_list,
48 NULL
49 }, **phase;
50 unsigned long flags;
51
52 /*
53 * Neither the BIOS, ourselves or any other kernel
54 * expects the system to be in execlists mode on startup,
55 * so we need to reset the GPU back to legacy mode. And the only
56 * known way to disable logical contexts is through a GPU reset.
57 *
58 * So in order to leave the system in a known default configuration,
59 * always reset the GPU upon unload and suspend. Afterwards we then
60 * clean up the GEM state tracking, flushing off the requests and
61 * leaving the system in a known idle state.
62 *
63 * Note that is of the upmost importance that the GPU is idle and
64 * all stray writes are flushed *before* we dismantle the backing
65 * storage for the pinned objects.
66 *
67 * However, since we are uncertain that resetting the GPU on older
68 * machines is a good idea, we don't - just in case it leaves the
69 * machine in an unusable condition.
70 */
71
72 intel_gt_suspend_late(&i915->gt);
73
74 spin_lock_irqsave(&i915->mm.obj_lock, flags);
75 for (phase = phases; *phase; phase++) {
76 LIST_HEAD(keep);
77
78 while ((obj = first_mm_object(*phase))) {
79 list_move_tail(&obj->mm.link, &keep);
80
81 /* Beware the background _i915_gem_free_objects */
82 if (!kref_get_unless_zero(&obj->base.refcount))
83 continue;
84
85 spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
86
87 i915_gem_object_lock(obj, NULL);
88 drm_WARN_ON(&i915->drm,
89 i915_gem_object_set_to_gtt_domain(obj, false));
90 i915_gem_object_unlock(obj);
91 i915_gem_object_put(obj);
92
93 spin_lock_irqsave(&i915->mm.obj_lock, flags);
94 }
95
96 list_splice_tail(&keep, *phase);
97 }
98 spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
99 }
100
i915_gem_resume(struct drm_i915_private * i915)101 void i915_gem_resume(struct drm_i915_private *i915)
102 {
103 GEM_TRACE("%s\n", dev_name(i915->drm.dev));
104
105 /*
106 * As we didn't flush the kernel context before suspend, we cannot
107 * guarantee that the context image is complete. So let's just reset
108 * it and start again.
109 */
110 intel_gt_resume(&i915->gt);
111 }
112