1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2023 Intel Corporation
4  */
5 
6 #include <drm/drm_atomic_helper.h>
7 
8 #include "i915_drv.h"
9 #include "intel_clock_gating.h"
10 #include "intel_cx0_phy.h"
11 #include "intel_display_driver.h"
12 #include "intel_display_reset.h"
13 #include "intel_display_types.h"
14 #include "intel_hotplug.h"
15 #include "intel_pps.h"
16 
17 static bool gpu_reset_clobbers_display(struct drm_i915_private *dev_priv)
18 {
19 	return (INTEL_INFO(dev_priv)->gpu_reset_clobbers_display &&
20 		intel_has_gpu_reset(to_gt(dev_priv)));
21 }
22 
23 void intel_display_reset_prepare(struct drm_i915_private *dev_priv)
24 {
25 	struct drm_modeset_acquire_ctx *ctx = &dev_priv->display.restore.reset_ctx;
26 	struct drm_atomic_state *state;
27 	int ret;
28 
29 	if (!HAS_DISPLAY(dev_priv))
30 		return;
31 
32 	/* reset doesn't touch the display */
33 	if (!dev_priv->display.params.force_reset_modeset_test &&
34 	    !gpu_reset_clobbers_display(dev_priv))
35 		return;
36 
37 	/* We have a modeset vs reset deadlock, defensively unbreak it. */
38 	set_bit(I915_RESET_MODESET, &to_gt(dev_priv)->reset.flags);
39 	smp_mb__after_atomic();
40 	wake_up_bit(&to_gt(dev_priv)->reset.flags, I915_RESET_MODESET);
41 
42 	if (atomic_read(&dev_priv->gpu_error.pending_fb_pin)) {
43 		drm_dbg_kms(&dev_priv->drm,
44 			    "Modeset potentially stuck, unbreaking through wedging\n");
45 		intel_gt_set_wedged(to_gt(dev_priv));
46 	}
47 
48 	/*
49 	 * Need mode_config.mutex so that we don't
50 	 * trample ongoing ->detect() and whatnot.
51 	 */
52 	mutex_lock(&dev_priv->drm.mode_config.mutex);
53 	drm_modeset_acquire_init(ctx, 0);
54 	while (1) {
55 		ret = drm_modeset_lock_all_ctx(&dev_priv->drm, ctx);
56 		if (ret != -EDEADLK)
57 			break;
58 
59 		drm_modeset_backoff(ctx);
60 	}
61 	/*
62 	 * Disabling the crtcs gracefully seems nicer. Also the
63 	 * g33 docs say we should at least disable all the planes.
64 	 */
65 	state = drm_atomic_helper_duplicate_state(&dev_priv->drm, ctx);
66 	if (IS_ERR(state)) {
67 		ret = PTR_ERR(state);
68 		drm_err(&dev_priv->drm, "Duplicating state failed with %i\n",
69 			ret);
70 		return;
71 	}
72 
73 	ret = drm_atomic_helper_disable_all(&dev_priv->drm, ctx);
74 	if (ret) {
75 		drm_err(&dev_priv->drm, "Suspending crtc's failed with %i\n",
76 			ret);
77 		drm_atomic_state_put(state);
78 		return;
79 	}
80 
81 	dev_priv->display.restore.modeset_state = state;
82 	state->acquire_ctx = ctx;
83 }
84 
85 void intel_display_reset_finish(struct drm_i915_private *i915)
86 {
87 	struct intel_display *display = &i915->display;
88 	struct drm_modeset_acquire_ctx *ctx = &display->restore.reset_ctx;
89 	struct drm_atomic_state *state;
90 	int ret;
91 
92 	if (!HAS_DISPLAY(i915))
93 		return;
94 
95 	/* reset doesn't touch the display */
96 	if (!test_bit(I915_RESET_MODESET, &to_gt(i915)->reset.flags))
97 		return;
98 
99 	state = fetch_and_zero(&display->restore.modeset_state);
100 	if (!state)
101 		goto unlock;
102 
103 	/* reset doesn't touch the display */
104 	if (!gpu_reset_clobbers_display(i915)) {
105 		/* for testing only restore the display */
106 		ret = drm_atomic_helper_commit_duplicated_state(state, ctx);
107 		if (ret) {
108 			drm_WARN_ON(&i915->drm, ret == -EDEADLK);
109 			drm_err(&i915->drm,
110 				"Restoring old state failed with %i\n", ret);
111 		}
112 	} else {
113 		/*
114 		 * The display has been reset as well,
115 		 * so need a full re-initialization.
116 		 */
117 		intel_pps_unlock_regs_wa(display);
118 		intel_display_driver_init_hw(display);
119 		intel_clock_gating_init(i915);
120 		intel_cx0_pll_power_save_wa(display);
121 		intel_hpd_init(i915);
122 
123 		ret = __intel_display_driver_resume(display, state, ctx);
124 		if (ret)
125 			drm_err(&i915->drm,
126 				"Restoring old state failed with %i\n", ret);
127 
128 		intel_hpd_poll_disable(i915);
129 	}
130 
131 	drm_atomic_state_put(state);
132 unlock:
133 	drm_modeset_drop_locks(ctx);
134 	drm_modeset_acquire_fini(ctx);
135 	mutex_unlock(&i915->drm.mode_config.mutex);
136 
137 	clear_bit_unlock(I915_RESET_MODESET, &to_gt(i915)->reset.flags);
138 }
139