[PATCH 3/3] drm/xe: Prepare display for D3Cold

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

Prepare power-well and DC handling for a full power
lost during D3Cold, then sanitize it upon D3->D0.
Otherwise we get a bunch of state mismatch.

Ideally we could leave DC9 enabled and wouldn't need
to move DC9->DC0 on every runtime resume, however,
the disable_DC is part of the power-well checks and
intrinsic to the dc_off power well. In the future that
can be detangled so we can have even bigger power savings.
But for now, let's focus on getting a D3Cold, which saves
much more power by itself.

v2: We cannot do the full-suspend-resume path or we end
with a deadlock between xe_gem_fault and the modeset-ioctl.
Reduce only to the power-well & DC sanitization.

Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
 drivers/gpu/drm/xe/display/xe_display.c | 22 ++++++++++++++++++++++
 drivers/gpu/drm/xe/display/xe_display.h |  4 ++++
 drivers/gpu/drm/xe/xe_pm.c              |  5 +++++
 3 files changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
index e4db069f0db3..a37cf679b087 100644
--- a/drivers/gpu/drm/xe/display/xe_display.c
+++ b/drivers/gpu/drm/xe/display/xe_display.c
@@ -362,6 +362,28 @@ void xe_display_pm_suspend_late(struct xe_device *xe)
 	intel_display_power_suspend_late(xe);
 }
 
+void xe_display_pm_runtime_suspend(struct xe_device *xe)
+{
+	if (!xe->info.enable_display)
+		return;
+
+	intel_power_domains_disable(xe);
+	intel_opregion_suspend(xe, PCI_D3cold);
+	intel_dmc_suspend(xe);
+	intel_power_domains_suspend(xe, PCI_D3cold);
+}
+
+void xe_display_pm_runtime_resume(struct xe_device *xe)
+{
+	if (!xe->info.enable_display)
+		return;
+
+	intel_power_domains_resume(xe);
+	intel_dmc_resume(xe);
+	intel_opregion_resume(xe);
+	intel_power_domains_enable(xe);
+}
+
 void xe_display_pm_resume_early(struct xe_device *xe)
 {
 	if (!xe->info.enable_display)
diff --git a/drivers/gpu/drm/xe/display/xe_display.h b/drivers/gpu/drm/xe/display/xe_display.h
index 710e56180b52..23b8e63a1703 100644
--- a/drivers/gpu/drm/xe/display/xe_display.h
+++ b/drivers/gpu/drm/xe/display/xe_display.h
@@ -38,6 +38,8 @@ void xe_display_pm_suspend(struct xe_device *xe);
 void xe_display_pm_suspend_late(struct xe_device *xe);
 void xe_display_pm_resume_early(struct xe_device *xe);
 void xe_display_pm_resume(struct xe_device *xe);
+void xe_display_pm_runtime_suspend(struct xe_device *xe);
+void xe_display_pm_runtime_resume(struct xe_device *xe);
 
 #else
 
@@ -67,6 +69,8 @@ static inline void xe_display_pm_suspend(struct xe_device *xe) {}
 static inline void xe_display_pm_suspend_late(struct xe_device *xe) {}
 static inline void xe_display_pm_resume_early(struct xe_device *xe) {}
 static inline void xe_display_pm_resume(struct xe_device *xe) {}
+static inline void xe_display_pm_runtime_suspend(struct xe_device *xe) {}
+static inline void xe_display_pm_runtime_resume(struct xe_device *xe) {}
 
 #endif /* CONFIG_DRM_XE_DISPLAY */
 #endif /* _XE_DISPLAY_H_ */
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 3e13a666fcc7..a13b97503467 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -342,6 +342,9 @@ int xe_pm_runtime_suspend(struct xe_device *xe)
 	}
 
 	xe_irq_suspend(xe);
+
+	if (xe->d3cold.allowed)
+		xe_display_pm_runtime_suspend(xe);
 out:
 	lock_map_release(&xe_device_mem_access_lockdep_map);
 	xe_pm_write_callback_task(xe, NULL);
@@ -380,6 +383,8 @@ int xe_pm_runtime_resume(struct xe_device *xe)
 				goto out;
 		}
 
+		xe_display_pm_runtime_resume(xe);
+
 		/*
 		 * This only restores pinned memory which is the memory
 		 * required for the GT(s) to resume.
-- 
2.43.2