drivers/gpu/drm/i915/i915_switcheroo.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright © 2019 Intel Corporation
   4  */
   5
   6 #include <linux/vga_switcheroo.h>
   7
   8 #include "i915_drv.h"
   9 #include "i915_switcheroo.h"
  10
  11 static void i915_switcheroo_set_state(struct pci_dev *pdev,
  12                                       enum vga_switcheroo_state state)
  13 {
  14         struct drm_i915_private *i915 = pdev_to_i915(pdev);
  15         pm_message_t pmm = { .event = PM_EVENT_SUSPEND };
  16
  17         if (!i915) {
  18                 dev_err(&pdev->dev, "DRM not initialized, aborting switch.\n");
  19                 return;
  20         }
  21
  22         if (state == VGA_SWITCHEROO_ON) {
  23                 drm_info(&i915->drm, "switched on\n");
  24                 i915->drm.switch_power_state = DRM_SWITCH_POWER_CHANGING;
  25                 /* i915 resume handler doesn't set to D0 */
  26                 pci_set_power_state(pdev, PCI_D0);
  27                 i915_resume_switcheroo(i915);
  28                 i915->drm.switch_power_state = DRM_SWITCH_POWER_ON;
  29         } else {
  30                 drm_info(&i915->drm, "switched off\n");
  31                 i915->drm.switch_power_state = DRM_SWITCH_POWER_CHANGING;
  32                 i915_suspend_switcheroo(i915, pmm);
  33                 i915->drm.switch_power_state = DRM_SWITCH_POWER_OFF;
  34         }
  35 }
  36
  37 static bool i915_switcheroo_can_switch(struct pci_dev *pdev)
  38 {
  39         struct drm_i915_private *i915 = pdev_to_i915(pdev);
  40
  41         /*
  42          * FIXME: open_count is protected by drm_global_mutex but that would lead to
  43          * locking inversion with the driver load path. And the access here is
  44          * completely racy anyway. So don't bother with locking for now.
  45          */
  46         return i915 && atomic_read(&i915->drm.open_count) == 0;
  47 }
  48
  49 static const struct vga_switcheroo_client_ops i915_switcheroo_ops = {
  50         .set_gpu_state = i915_switcheroo_set_state,
  51         .reprobe = NULL,
  52         .can_switch = i915_switcheroo_can_switch,
  53 };
  54
  55 int i915_switcheroo_register(struct drm_i915_private *i915)
  56 {
  57         struct pci_dev *pdev = i915->drm.pdev;
  58
  59         return vga_switcheroo_register_client(pdev, &i915_switcheroo_ops, false);
  60 }
  61
  62 void i915_switcheroo_unregister(struct drm_i915_private *i915)
  63 {
  64         struct pci_dev *pdev = i915->drm.pdev;
  65
  66         vga_switcheroo_unregister_client(pdev);
  67 }