Kyösti Mälkki has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/36221 )
Change subject: WIP: Add configurable ramstage support for minimal PCI scanning ......................................................................
Patch Set 11:
(1 comment)
https://review.coreboot.org/c/coreboot/+/36221/11/src/device/pci_device.c File src/device/pci_device.c:
https://review.coreboot.org/c/coreboot/+/36221/11/src/device/pci_device.c@94... PS11, Line 947: dev->enabled = 0; You probably should never clear dev->enabled in connection with MINIMAL_PCI_SCANNING=y. This is connected to mechanisms of completely disabling said PCI functions in the hardware, i.e. they will become inaccessible even for payloads.
This approach may have the same symptomps of not creating ACPI namespace objects and not programming PCI subsystem IDs as the approach of skipping the PCI device ID probe completely.
I may not have said or even realised this before, but approach here requires that any PCI device ID with problematic resources has to be explicitly added as a dummy driver. We cannot roll firmware updates every time a new PCIe graphics card hits the shelfs, so using device ID (alone at least) as a criteria for scanning seems like a doomed idea...
In some of the comments, Aaron pointed out hooking into .read_resources. That might be the best suggestion so far.