xref: /linux/drivers/gpu/drm/i915/i915_switcheroo.c (revision a4eb44a6435d6d8f9e642407a4a06f65eb90ca04)
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 
23 	if (state == VGA_SWITCHEROO_ON) {
24 		drm_info(&i915->drm, "switched on\n");
25 		i915->drm.switch_power_state = DRM_SWITCH_POWER_CHANGING;
26 		/* i915 resume handler doesn't set to D0 */
27 		pci_set_power_state(pdev, PCI_D0);
28 		i915_driver_resume_switcheroo(i915);
29 		i915->drm.switch_power_state = DRM_SWITCH_POWER_ON;
30 	} else {
31 		drm_info(&i915->drm, "switched off\n");
32 		i915->drm.switch_power_state = DRM_SWITCH_POWER_CHANGING;
33 		i915_driver_suspend_switcheroo(i915, pmm);
34 		i915->drm.switch_power_state = DRM_SWITCH_POWER_OFF;
35 	}
36 }
37 
38 static bool i915_switcheroo_can_switch(struct pci_dev *pdev)
39 {
40 	struct drm_i915_private *i915 = pdev_to_i915(pdev);
41 
42 	/*
43 	 * FIXME: open_count is protected by drm_global_mutex but that would lead to
44 	 * locking inversion with the driver load path. And the access here is
45 	 * completely racy anyway. So don't bother with locking for now.
46 	 */
47 	return i915 && atomic_read(&i915->drm.open_count) == 0;
48 }
49 
50 static const struct vga_switcheroo_client_ops i915_switcheroo_ops = {
51 	.set_gpu_state = i915_switcheroo_set_state,
52 	.reprobe = NULL,
53 	.can_switch = i915_switcheroo_can_switch,
54 };
55 
56 int i915_switcheroo_register(struct drm_i915_private *i915)
57 {
58 	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
59 
60 	return vga_switcheroo_register_client(pdev, &i915_switcheroo_ops, false);
61 }
62 
63 void i915_switcheroo_unregister(struct drm_i915_private *i915)
64 {
65 	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
66 
67 	vga_switcheroo_unregister_client(pdev);
68 }
69