From: Bjorn Helgaas Date: Fri, 19 Sep 2014 16:56:06 +0000 (-0600) Subject: Revert "PCI: Don't scan random busses in pci_scan_bridge()" X-Git-Tag: fixes-for-v3.18-merge-window~74^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7a0b33d4a45d30b9a838fba4efcd80b7b57d4d16;p=pandora-kernel.git Revert "PCI: Don't scan random busses in pci_scan_bridge()" This reverts commit fc1b253141b3 ("PCI: Don't scan random busses in pci_scan_bridge()") because it breaks CardBus on some machines. David tested a Dell Latitude D505 that worked like this prior to fc1b253141b3: pci 0000:00:1e.0: PCI bridge to [bus 01] pci 0000:01:01.0: CardBus bridge to [bus 02-05] Note that the 01:01.0 CardBus bridge has a bus number aperture of [bus 02-05], but those buses are all outside the 00:1e.0 PCI bridge bus number aperture, so accesses to buses 02-05 never reach CardBus. This is later patched up by yenta_fixup_parent_bridge(), which changes the subordinate bus number of the 00:1e.0 PCI bridge: pci_bus 0000:01: Raising subordinate bus# of parent bus (#01) from #01 to #05 With fc1b253141b3, pci_scan_bridge() fails immediately when it notices that we can't allocate a valid secondary bus number for the CardBus bridge, and CardBus doesn't work at all: pci 0000:01:01.0: can't allocate child bus 01 from [bus 01] I'd prefer to fix this by integrating the yenta_fixup_parent_bridge() logic into pci_scan_bridge() so we fix the bus number apertures up front. But I don't think we can do that before v3.17, so I'm going to revert this to avoid the problem while we're working on the long-term fix. Link: https://bugzilla.kernel.org/show_bug.cgi?id=83441 Link: http://lkml.kernel.org/r/1409303414-5196-1-git-send-email-david.henningsson@canonical.com Reported-by: David Henningsson Tested-by: David Henningsson Signed-off-by: Bjorn Helgaas CC: stable@vger.kernel.org # v3.15+ --- Reading git-diff-tree failed