[REGRESSION 6.14] Some PCI device BARs inacessible

From: Michał Pecio
Date: Fri Apr 18 2025 - 04:29:44 EST


Hi,

This is a heads up that an apparent PCI regression has been reported
and mistakenly assigned to USB in the kernel bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=220016

Visible symptom is missing USB devices, but the whole controller fails
to probe, apparently due to devm_request_mem_region() returning NULL,
see drivers/usb/core/hcd-pci.c and usb_hcd_pci_probe().

Same systems also show a similar failure with some AHCI controller.
It seems specific to particular ASUS AMD motherboards.

Somebody found that disabling CONFIG_PCI_REALLOC_ENABLE_AUTO helps.

That's all I know, reporters can be reached via bugzilla.

Regards,
Michal