From: Bjorn Helgaas <helg...@kernel.org> Date: Tue, 15 Aug 2017 12:03:31 -0500
> On Tue, Aug 15, 2017 at 11:24:48PM +0800, Ding Tianhong wrote: >> Eric report a oops when booting the system after applying >> the commit a99b646afa8a ("PCI: Disable PCIe Relaxed..."): >> ... > >> It looks like the pci_find_pcie_root_port() was trying to >> find the Root Port for the PCI device which is the Root >> Port already, it will return NULL and trigger the problem, >> so check the highest_pcie_bridge to fix thie problem. > > The problem was actually with a Root Complex Integrated Endpoint that > has no upstream PCIe device: > > 00:05.2 System peripheral: Intel Corporation Device 0e2a (rev 04) > Subsystem: Intel Corporation Device 0e2a > Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- > Stepping- SERR- FastB2B- DisINTx- > Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- > <TAbort- <MAbort- >SERR- <PERR- INTx- > Capabilities: [40] Express (v2) Root Complex Integrated Endpoint, MSI > 00 > DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <64ns, > L1 <1us > ExtTag- RBE- FLReset- > DevCtl: Report errors: Correctable- Non-Fatal- Fatal+ > Unsupported+ > RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ > MaxPayload 128 bytes, MaxReadReq 128 bytes > >> Fixes: a99b646afa8a ("PCI: Disable PCIe Relaxed Ordering if unsupported") > > This also > > Fixes: c56d4450eb68 ("PCI: Turn off Request Attributes to avoid Chelsio T5 > Completion erratum") > > which added pci_find_pcie_root_port(). Prior to this Relaxed Ordering > series, we only used pci_find_pcie_root_port() in a Chelsio quirk that > only applied to non-integrated endpoints, so we didn't trip over the > bug. ... > I think structuring the fix as follows is a little more readable: > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index af0cc3456dc1..587cd7623ed8 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c I've integrated all of this feedback and the other Fixes: tag and applied it to 'net', thanks.