xref: /openbmc/linux/drivers/gpu/drm/i915/gt/intel_gt_pm.c (revision b8d312aa)
1 /*
2  * SPDX-License-Identifier: MIT
3  *
4  * Copyright © 2019 Intel Corporation
5  */
6 
7 #include "i915_drv.h"
8 #include "i915_params.h"
9 #include "intel_engine_pm.h"
10 #include "intel_gt.h"
11 #include "intel_gt_pm.h"
12 #include "intel_pm.h"
13 #include "intel_wakeref.h"
14 
15 static void pm_notify(struct drm_i915_private *i915, int state)
16 {
17 	blocking_notifier_call_chain(&i915->gt.pm_notifications, state, i915);
18 }
19 
20 static int __gt_unpark(struct intel_wakeref *wf)
21 {
22 	struct intel_gt *gt = container_of(wf, typeof(*gt), wakeref);
23 	struct drm_i915_private *i915 = gt->i915;
24 
25 	GEM_TRACE("\n");
26 
27 	/*
28 	 * It seems that the DMC likes to transition between the DC states a lot
29 	 * when there are no connected displays (no active power domains) during
30 	 * command submission.
31 	 *
32 	 * This activity has negative impact on the performance of the chip with
33 	 * huge latencies observed in the interrupt handler and elsewhere.
34 	 *
35 	 * Work around it by grabbing a GT IRQ power domain whilst there is any
36 	 * GT activity, preventing any DC state transitions.
37 	 */
38 	gt->awake = intel_display_power_get(i915, POWER_DOMAIN_GT_IRQ);
39 	GEM_BUG_ON(!gt->awake);
40 
41 	intel_enable_gt_powersave(i915);
42 
43 	i915_update_gfx_val(i915);
44 	if (INTEL_GEN(i915) >= 6)
45 		gen6_rps_busy(i915);
46 
47 	i915_pmu_gt_unparked(i915);
48 
49 	intel_gt_queue_hangcheck(gt);
50 
51 	pm_notify(i915, INTEL_GT_UNPARK);
52 
53 	return 0;
54 }
55 
56 static int __gt_park(struct intel_wakeref *wf)
57 {
58 	struct drm_i915_private *i915 =
59 		container_of(wf, typeof(*i915), gt.wakeref);
60 	intel_wakeref_t wakeref = fetch_and_zero(&i915->gt.awake);
61 
62 	GEM_TRACE("\n");
63 
64 	pm_notify(i915, INTEL_GT_PARK);
65 
66 	i915_pmu_gt_parked(i915);
67 	if (INTEL_GEN(i915) >= 6)
68 		gen6_rps_idle(i915);
69 
70 	/* Everything switched off, flush any residual interrupt just in case */
71 	intel_synchronize_irq(i915);
72 
73 	GEM_BUG_ON(!wakeref);
74 	intel_display_power_put(i915, POWER_DOMAIN_GT_IRQ, wakeref);
75 
76 	return 0;
77 }
78 
79 static const struct intel_wakeref_ops wf_ops = {
80 	.get = __gt_unpark,
81 	.put = __gt_park,
82 	.flags = INTEL_WAKEREF_PUT_ASYNC,
83 };
84 
85 void intel_gt_pm_init_early(struct intel_gt *gt)
86 {
87 	intel_wakeref_init(&gt->wakeref, &gt->i915->runtime_pm, &wf_ops);
88 
89 	BLOCKING_INIT_NOTIFIER_HEAD(&gt->pm_notifications);
90 }
91 
92 static bool reset_engines(struct intel_gt *gt)
93 {
94 	if (INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
95 		return false;
96 
97 	return __intel_gt_reset(gt, ALL_ENGINES) == 0;
98 }
99 
100 /**
101  * intel_gt_sanitize: called after the GPU has lost power
102  * @gt: the i915 GT container
103  * @force: ignore a failed reset and sanitize engine state anyway
104  *
105  * Anytime we reset the GPU, either with an explicit GPU reset or through a
106  * PCI power cycle, the GPU loses state and we must reset our state tracking
107  * to match. Note that calling intel_gt_sanitize() if the GPU has not
108  * been reset results in much confusion!
109  */
110 void intel_gt_sanitize(struct intel_gt *gt, bool force)
111 {
112 	struct intel_engine_cs *engine;
113 	enum intel_engine_id id;
114 
115 	GEM_TRACE("\n");
116 
117 	intel_uc_sanitize(&gt->uc);
118 
119 	if (!reset_engines(gt) && !force)
120 		return;
121 
122 	for_each_engine(engine, gt->i915, id)
123 		__intel_engine_reset(engine, false);
124 }
125 
126 int intel_gt_resume(struct intel_gt *gt)
127 {
128 	struct intel_engine_cs *engine;
129 	enum intel_engine_id id;
130 	int err = 0;
131 
132 	/*
133 	 * After resume, we may need to poke into the pinned kernel
134 	 * contexts to paper over any damage caused by the sudden suspend.
135 	 * Only the kernel contexts should remain pinned over suspend,
136 	 * allowing us to fixup the user contexts on their first pin.
137 	 */
138 	intel_gt_pm_get(gt);
139 	for_each_engine(engine, gt->i915, id) {
140 		struct intel_context *ce;
141 
142 		intel_engine_pm_get(engine);
143 
144 		ce = engine->kernel_context;
145 		if (ce)
146 			ce->ops->reset(ce);
147 
148 		engine->serial++; /* kernel context lost */
149 		err = engine->resume(engine);
150 
151 		intel_engine_pm_put(engine);
152 		if (err) {
153 			dev_err(gt->i915->drm.dev,
154 				"Failed to restart %s (%d)\n",
155 				engine->name, err);
156 			break;
157 		}
158 	}
159 	intel_gt_pm_put(gt);
160 
161 	return err;
162 }
163 
164 void intel_gt_runtime_suspend(struct intel_gt *gt)
165 {
166 	intel_uc_runtime_suspend(&gt->uc);
167 }
168 
169 int intel_gt_runtime_resume(struct intel_gt *gt)
170 {
171 	intel_gt_init_swizzling(gt);
172 
173 	return intel_uc_runtime_resume(&gt->uc);
174 }
175