Hi Bjorn, Here is the public bug. https://bugzilla.kernel.org/show_bug.cgi?id=200769 Best regards, AceLan Kao. 2018-08-09 2:00 GMT+08:00 Bjorn Helgaas <helgaas@xxxxxxxxxx>: > On Wed, Aug 08, 2018 at 01:48:37PM +0800, AceLan Kao wrote: >> There are some 0 resource size pci devices, and it leads to the >> accumulator fails to maintain the correct value. >> It results in a strange issue on my machine that xhci_hcd failed to init. >> [ 2.437278] xhci_hcd 0000:05:00.0: init 0000:05:00.0 fail, -16 >> [ 2.437300] xhci_hcd: probe of 0000:05:00.0 failed with error -16 > > I don't think it's possible for a PCI device to have a BAR of zero > size. Bits 0-3 of memory BARs are read-only, leading to a minimum BAR > size of 16 bytes; similarly, bits 0-1 of I/O BARs are read-only, > giving a minimum size of 4 ports. > > My guess is that if you have a pci_dev with a resource that looks like > it's valid but has zero size, that resource came from OF or device > tree. If that's the case, I'd say we should fix the OF or DT parsing > code to reject those resources. If we do that, we shouldn't need the > patch below. > > Can you open a bugzilla.kernel.org report and attach the complete > dmesg log leading up to this, as well as the "sudo lspci -vv" output > for this device? It should have clues about how we got here. > >> To fix this, check if the resource size equals to 0, doesn't increase size. >> >> Fixes: c9c75143a596 ("PCI: Fix calculation of bridge window's size and alignment") >> CC: stable@xxxxxxxxxxxxxxx # 4.14+ >> >> Signed-off-by: AceLan Kao <acelan.kao@xxxxxxxxxxxxx> >> --- >> drivers/pci/setup-bus.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c >> index 79b1824e83b4..ae05dde8c6e3 100644 >> --- a/drivers/pci/setup-bus.c >> +++ b/drivers/pci/setup-bus.c >> @@ -1061,7 +1061,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, >> r->flags = 0; >> continue; >> } >> - size += max(r_size, align); >> + if (r_size != 0) >> + size += max(r_size, align); >> /* Exclude ranges with size > align from >> calculation of the alignment. */ >> if (r_size <= align) >> -- >> 2.17.1 >>
