[PATCH] drm/xe/pm: Enable RPM via PCIe PM capability

[Gupta, Anshuman]

> -----Original Message-----
> From: K V P, Satyanarayana <satyanarayana.k.v.p at intel.com>
> Sent: Wednesday, July 30, 2025 6:03 PM
> To: intel-xe at lists.freedesktop.org
> Cc: K V P, Satyanarayana <satyanarayana.k.v.p at intel.com>; Wajdeczko, Michal
> <Michal.Wajdeczko at intel.com>; Brost, Matthew <matthew.brost at intel.com>;
> Winiarski, Michal <michal.winiarski at intel.com>; Gupta, Anshuman
> <anshuman.gupta at intel.com>
> Subject: [PATCH] drm/xe/pm: Enable RPM via PCIe PM capability
> 
> Enable Runtime Power Management (RPM) for PCI Express devices by utilizing
> their native Power Management (PM) capabilities.
> 
> Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p at intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Matthew Brost <matthew.brost at intel.com>
> Cc: Michał Winiarski <michal.winiarski at intel.com>
> Cc: Anshuman Gupta <anshuman.gupta at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_device_types.h | 2 ++
>  drivers/gpu/drm/xe/xe_pm.c           | 9 +++++++++
>  drivers/gpu/drm/xe/xe_pm.h           | 4 ++++
>  3 files changed, 15 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h
> b/drivers/gpu/drm/xe/xe_device_types.h
> index 38c8329b4d2c..3bbfc46044a0 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -285,6 +285,8 @@ struct xe_device {
>  		 * pcode mailbox commands.
>  		 */
>  		u8 has_mbx_power_limits:1;
> +		/** @info.has_pm_capability: Device has PCI pm capability */
> +		u8 has_pm_capability:1;
>  		/** @info.has_pxp: Device has PXP support */
>  		u8 has_pxp:1;
>  		/** @info.has_range_tlb_invalidation: Has range based TLB
> invalidations */ diff --git a/drivers/gpu/drm/xe/xe_pm.c
> b/drivers/gpu/drm/xe/xe_pm.c index 44aaf154ddf7..5e6311964685 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -244,6 +244,9 @@ static void xe_pm_runtime_init(struct xe_device *xe)  {
>  	struct device *dev = xe->drm.dev;
> 
> +	if (!IS_RPM_SUPPORTED(xe))
> +		return;
> +
>  	/*
>  	 * Disable the system suspend direct complete optimization.
>  	 * We need to ensure that the regular device suspend/resume
> functions @@ -265,6 +268,7 @@ static void xe_pm_runtime_init(struct
> xe_device *xe)
> 
>  int xe_pm_init_early(struct xe_device *xe)  {
> +	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
>  	int err;
> 
>  	INIT_LIST_HEAD(&xe->mem_access.vram_userfault.list);
> @@ -278,6 +282,8 @@ int xe_pm_init_early(struct xe_device *xe)
>  		return err;
> 
>  	xe->d3cold.capable = xe_pm_pci_d3cold_capable(xe);
> +	xe->info.has_pm_capability = !!pdev->pm_cap;
> +
>  	return 0;
>  }
>  ALLOW_ERROR_INJECTION(xe_pm_init_early, ERRNO); /* See xe_pci_probe()
> */ @@ -364,6 +370,9 @@ static void xe_pm_runtime_fini(struct xe_device *xe)
> {
>  	struct device *dev = xe->drm.dev;
> 
> +	if (!IS_RPM_SUPPORTED(xe))
> +		return;
> +
>  	pm_runtime_get_sync(dev);
>  	pm_runtime_forbid(dev);
>  }
> diff --git a/drivers/gpu/drm/xe/xe_pm.h b/drivers/gpu/drm/xe/xe_pm.h index
> 59678b310e55..55b65728f522 100644
> --- a/drivers/gpu/drm/xe/xe_pm.h
> +++ b/drivers/gpu/drm/xe/xe_pm.h
> @@ -9,6 +9,10 @@
>  #include <linux/pm_runtime.h>
> 
>  #define DEFAULT_VRAM_THRESHOLD 300 /* in MB */
> +#define IS_RPM_SUPPORTED(xe) ({ \
> +		struct xe_device *___xe = (xe); \
> +		___xe->info.has_pm_capability; \
> +		})
IMHO the correct method to let PCIe core get the permanent ref count if pdev->pm_cap is false.
@Vivi, Rodrigo what your thought, I think XeKMD should not take any decision based upon pdev->pm_cap.
Thanks,
Anshuman 
> 
>  struct xe_device;
> 
> --
> 2.43.0