From mboxrd@z Thu Jan 1 00:00:00 1970 From: benh@kernel.crashing.org (Benjamin Herrenschmidt) Date: Tue, 30 Sep 2014 08:31:52 +1000 Subject: [PATCH v13 10/12] PCI: Assign unassigned bus resources in pci_scan_root_bus() In-Reply-To: References: <1412000971-9242-1-git-send-email-Liviu.Dudau@arm.com> <1412000971-9242-11-git-send-email-Liviu.Dudau@arm.com> <1412024521.4285.98.camel@pasglop> Message-ID: <1412029912.4285.110.camel@pasglop> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 2014-09-29 at 15:33 -0600, Bjorn Helgaas wrote: > > Right and on powerpc and others as well. We need to survey existing > > resources. We also have a number of platform things that might need > > to happen before we do the final re-assignment pass. > > That's true today. But I don't know whether it *has* to be this way > forever. On x86, pcibios_resource_survey() throws in E820 information > (which we know long before we do any PCI enumeration) and some IO-APIC > resources (it looks like we also know these before PCI enumeration). > Powerpc has pcibios_reserve_legacy_regions(), but that looks like > mostly stuff that could be done when we find the host bridge, before > we enumerate PCI devices below it. Oh we can probably change that but it's going to be much more work than just moving the assignment into pci_scan_root_bus(). There are also a number of subtle and not-so-subtle bits of code that rely on side effects of the current code such as anything that tests for bus->added or dev->added. Again, nothing we can't sort out eventually but the transition might be a bit painful. We might need to introduce a new flag for platforms converted to the "new style" generalized resource assignment which we can deprecate once everybody has moved over. Cheers, Ben.