drm/i915: add comments on what stage a given PM handler is called

This will hopefully make it easier to navigate the code without the need
to consult the full PM documentation.

v2:
- add a comment that the freeze handler is also called after rebooting
- add a comment that the thaw handler is also called to recover from
  errors (Ville)
- add the PM event names (PMSG_THAW etc.) for reference (Ville)
- add comments that s0ix can be handled both via system and runtime
  suspend (Ville)

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index bce58d395b28c9896cfaf12dd49e3d9d3e83df55..035ec94ca3c7d9bb725abd88169a965b2203ba91 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1534,10 +1534,30 @@ static int intel_resume_prepare(struct drm_i915_private *dev_priv,
 }
 
 static const struct dev_pm_ops i915_pm_ops = {
+       /*
+        * S0ix (via system suspend) and S3 event handlers [PMSG_SUSPEND,
+        * PMSG_RESUME]
+        */
        .suspend = i915_pm_suspend,
        .suspend_late = i915_pm_suspend_late,
        .resume_early = i915_pm_resume_early,
        .resume = i915_pm_resume,
+
+       /*
+        * S4 event handlers
+        * @freeze, @freeze_late    : called (1) before creating the
+        *                            hibernation image [PMSG_FREEZE] and
+        *                            (2) after rebooting, before restoring
+        *                            the image [PMSG_QUIESCE]
+        * @thaw, @thaw_early       : called (1) after creating the hibernation
+        *                            image, before writing it [PMSG_THAW]
+        *                            and (2) after failing to create or
+        *                            restore the image [PMSG_RECOVER]
+        * @poweroff, @poweroff_late: called after writing the hibernation
+        *                            image, before rebooting [PMSG_HIBERNATE]
+        * @restore, @restore_early : called after rebooting and restoring the
+        *                            hibernation image [PMSG_RESTORE]
+        */
        .freeze = i915_pm_suspend,
        .freeze_late = i915_pm_suspend_late,
        .thaw_early = i915_pm_resume_early,
@@ -1546,6 +1566,8 @@ static const struct dev_pm_ops i915_pm_ops = {
        .poweroff_late = i915_pm_suspend_late,
        .restore_early = i915_pm_resume_early,
        .restore = i915_pm_resume,
+
+       /* S0ix (via runtime suspend) event handlers */
        .runtime_suspend = intel_runtime_suspend,
        .runtime_resume = intel_runtime_resume,
 };