On 06/03/2016 08:32 AM, Gabriele Paoloni wrote:
[...]

quoted

quoted

+struct pci_ecam_ops *pci_mcfg_get_ops(struct acpi_pci_root *root)
+{
+	int bus_num = root->secondary.start;
+	int domain = root->segment;
+	struct pci_cfg_fixup *f;
+
+	if (!mcfg_table)
+		return &pci_generic_ecam_ops;
+
+	/*
+	 * Match against platform specific quirks and return

corresponding

quoted

+	 * CAM ops.
+	 *
+	 * First match against PCI topology <domain:bus> then use OEM ID

and

quoted

+	 * OEM revision from MCFG table standard header.
+	 */
+	for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups;

f++) {

quoted

+		if ((f->domain == domain || f->domain ==

PCI_MCFG_DOMAIN_ANY) &&

quoted

+		    (f->bus_num == bus_num || f->bus_num ==

PCI_MCFG_BUS_ANY) &&

quoted

+		    (!strncmp(f->oem_id, mcfg_table->header.oem_id,
+			      ACPI_OEM_ID_SIZE)) &&
+		    (f->oem_revision == mcfg_table->header.oem_revision))

Is this more likely to be updated between quirky and fixed platforms
than oem_table_id? What do folks think about using oem_table_id instead
of, or in addition to, oem_revision?

 From my understanding we need to stick to this mechanism as (otherwise)
there are platforms out in the field that would need a FW update.

So I don't think that using oem_table_id "instead" is possible; about
"in addition" I think it is doable, but I do not see the advantage much.
I mean that if a platform gets fixed the oem revision should change too,
Right?

I think you are correct.  My take away on discussions about using this 
style of quirk matching was that we would require the oem_revision to 
change as different quirks (or lack of quirks) were required.

David Daney

Thanks

Gab