[Intel-xe] [PATCH] drm/xe/pm: give the core kernel its rpm ref back

[Matthew Auld]

In local_pci_probe() the core kernel increments the rpm for the device,
just before calling into the probe hook. If the driver/device supports
runtime pm it is then meant to drop this ref during probe (like we do in
xe_pm_runtime_init()). However when removing the device we then also need
to give the reference back, otherwise the ref that is dropped in
pci_device_remove() will be unbalanced when for example unloading the
driver, leading to warnings like:

    [ 3808.596345] xe 0000:03:00.0: Runtime PM usage count underflow!

Fix this by incrementing the rpm ref when removing the device.

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/193
Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/xe/xe_pci.c | 1 +
 drivers/gpu/drm/xe/xe_pm.c  | 7 +++++++
 drivers/gpu/drm/xe/xe_pm.h  | 1 +
 3 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
index 25598de3a1fc..85d337cd8fbe 100644
--- a/drivers/gpu/drm/xe/xe_pci.c
+++ b/drivers/gpu/drm/xe/xe_pci.c
@@ -441,6 +441,7 @@ static void xe_pci_remove(struct pci_dev *pdev)
 		return;
 
 	xe_device_remove(xe);
+	xe_pm_runtime_fini(xe);
 	pci_set_drvdata(pdev, NULL);
 }
 
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 44c38e670587..73d81621d960 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -128,6 +128,13 @@ void xe_pm_runtime_init(struct xe_device *xe)
 	pm_runtime_put_autosuspend(dev);
 }
 
+void xe_pm_runtime_fini(struct xe_device *xe)
+{
+	struct device *dev = xe->drm.dev;
+
+	pm_runtime_get_sync(dev);
+}
+
 int xe_pm_runtime_suspend(struct xe_device *xe)
 {
 	struct xe_gt *gt;
diff --git a/drivers/gpu/drm/xe/xe_pm.h b/drivers/gpu/drm/xe/xe_pm.h
index b8c5f9558e26..6a885585f653 100644
--- a/drivers/gpu/drm/xe/xe_pm.h
+++ b/drivers/gpu/drm/xe/xe_pm.h
@@ -14,6 +14,7 @@ int xe_pm_suspend(struct xe_device *xe);
 int xe_pm_resume(struct xe_device *xe);
 
 void xe_pm_runtime_init(struct xe_device *xe);
+void xe_pm_runtime_fini(struct xe_device *xe);
 int xe_pm_runtime_suspend(struct xe_device *xe);
 int xe_pm_runtime_resume(struct xe_device *xe);
 int xe_pm_runtime_get(struct xe_device *xe);
-- 
2.39.1