Unverified Commit 14fcd736 authored by Satyanarayana K V P's avatar Satyanarayana K V P Committed by Rodrigo Vivi
Browse files

drm/xe/pm: Disable RPM for SR-IOV VFs 



VFs without native PCIe Power Management (PM) capabilities inherit their
PF's power state as per PCIe specifications(§5.10.1 PCIe Base Spec 7.0).
Enabling Runtime Power Management (RPM) for these VFs trigger unnecessary
driver suspend/resume operations that ultimately perform no PCI-level power
transition.

Since VFs without PM capabilities cannot independently enter low-power
states, the existing RPM workflow becomes redundant:
1. Driver executes full suspend/resume sequence
2. PCI PM transition step becomes no-op
3. VF power state remains tied to PF's status

Disabling RPM for VFs eliminates this redundant processing while
maintaining proper power management through PF dependency. This
optimization ensures VFs follow their PF's power state without superfluous
runtime handling.

Signed-off-by: default avatarSatyanarayana K V P <satyanarayana.k.v.p@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Maarten Lankhorst <dev@lankhorst.se>
Reviewed-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20250812163613.9954-1-satyanarayana.k.v.p@intel.com


Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
parent cc8b2211

drivers/gpu/drm/xe/xe_pm.c

+8 −0
Original line number Diff line number Diff line
@@ -247,6 +247,10 @@ static void xe_pm_runtime_init(struct xe_device *xe) 
{

	struct device *dev = xe->drm.dev;



	/* Our current VFs do not support RPM. so, disable it */

	if (IS_SRIOV_VF(xe))

		return;



	/*

	 * Disable the system suspend direct complete optimization.

	 * We need to ensure that the regular device suspend/resume functions
@@ -371,6 +375,10 @@ static void xe_pm_runtime_fini(struct xe_device *xe) 
{

	struct device *dev = xe->drm.dev;



	/* Our current VFs do not support RPM. so, disable it */

	if (IS_SRIOV_VF(xe))

		return;



	pm_runtime_get_sync(dev);

	pm_runtime_forbid(dev);

}