1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2019 Intel Corporation
4  */
5 
6 #include <linux/vga_switcheroo.h>
7 
8 #include "i915_driver.h"
9 #include "i915_drv.h"
10 #include "i915_switcheroo.h"
11 
12 static void i915_switcheroo_set_state(struct pci_dev *pdev,
13 				      enum vga_switcheroo_state state)
14 {
15 	struct drm_i915_private *i915 = pdev_to_i915(pdev);
16 	pm_message_t pmm = { .event = PM_EVENT_SUSPEND };
17 
18 	if (!i915) {
19 		dev_err(&pdev->dev, "DRM not initialized, aborting switch.\n");
20 		return;
21 	}
22 	if (!HAS_DISPLAY(i915)) {
23 		dev_err(&pdev->dev, "Device state not initialized, aborting switch.\n");
24 		return;
25 	}
26 
27 	if (state == VGA_SWITCHEROO_ON) {
28 		drm_info(&i915->drm, "switched on\n");
29 		i915->drm.switch_power_state = DRM_SWITCH_POWER_CHANGING;
30 		/* i915 resume handler doesn't set to D0 */
31 		pci_set_power_state(pdev, PCI_D0);
32 		i915_driver_resume_switcheroo(i915);
33 		i915->drm.switch_power_state = DRM_SWITCH_POWER_ON;
34 	} else {
35 		drm_info(&i915->drm, "switched off\n");
36 		i915->drm.switch_power_state = DRM_SWITCH_POWER_CHANGING;
37 		i915_driver_suspend_switcheroo(i915, pmm);
38 		i915->drm.switch_power_state = DRM_SWITCH_POWER_OFF;
39 	}
40 }
41 
42 static bool i915_switcheroo_can_switch(struct pci_dev *pdev)
43 {
44 	struct drm_i915_private *i915 = pdev_to_i915(pdev);
45 
46 	/*
47 	 * FIXME: open_count is protected by drm_global_mutex but that would lead to
48 	 * locking inversion with the driver load path. And the access here is
49 	 * completely racy anyway. So don't bother with locking for now.
50 	 */
51 	return i915 && HAS_DISPLAY(i915) && atomic_read(&i915->drm.open_count) == 0;
52 }
53 
54 static const struct vga_switcheroo_client_ops i915_switcheroo_ops = {
55 	.set_gpu_state = i915_switcheroo_set_state,
56 	.reprobe = NULL,
57 	.can_switch = i915_switcheroo_can_switch,
58 };
59 
60 int i915_switcheroo_register(struct drm_i915_private *i915)
61 {
62 	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
63 
64 	return vga_switcheroo_register_client(pdev, &i915_switcheroo_ops, false);
65 }
66 
67 void i915_switcheroo_unregister(struct drm_i915_private *i915)
68 {
69 	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
70 
71 	vga_switcheroo_unregister_client(pdev);
72 }
73