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_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 }