Re: [PATCH v2 1/5] drm/xe/pm: initialize the device's system wakeup capabilities

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Device wakeup capability is enabled unconditionally for all platforms and VFs, falsely advertising PME capability and breaking HPD polling on unsupported platforms.
--

commit 3d9bcb78036d2ff7f08956912516e90ce3bea87a
Author: Vinod Govindapillai <vinod.govindapillai@intel.com>

drm/xe/pm: initialize the device's system wakeup capabilities

This commit enables the device as a wakeup device to allow display hotplugs
to generate PME events for NVL+ hardware.

> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index 1e04e8ef2611f..009271ce532c6 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -1216,6 +1216,10 @@ static int __xe_pci_probe(struct pci_dev *pdev, const struct xe_device_desc *des
>  
>  	pci_set_master(pdev);
>  
> +	err = devm_device_init_wakeup(&pdev->dev);
> +	if (err)
> +		return err;
> +

[Severity: High]
Does enabling wakeup unconditionally here falsely advertise PME capabilities
for unsupported platforms (e.g., DG2, MTL, LNL) and SR-IOV VFs?

By calling devm_device_init_wakeup() in __xe_pci_probe(), the driver sets
dev->power.can_wakeup = true for every xe device. Later, during
xe_pci_runtime_suspend(), the code checks:

    pme_capable = pci_enable_wake(pdev, state, true) == 0;

Because wakeup is enabled by default, pci_enable_wake() will incorrectly
return 0 (success) on older PCIe platforms that report standard PCI PM
capabilities.

This erroneously sets pme_capable = true, which is passed to
xe_display_set_pme_capable(). Since intel_hpd_poll_enable() skips polling
if the device is marked PME capable, could this cause hotplug events to be
completely missed during suspend on pre-NVL platforms that cannot actually
generate PMEs from HPDs?

>  	err = xe_probe_info_early(xe, desc, &probed_info);
>  	if (err)
>  		return err;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260903080410.489411-1-vinod.govindapillai@intel.com?part=1