> -----Original Message----- > From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx] > Sent: Friday, February 23, 2018 11:26 AM > To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx> > Cc: bhelgaas@xxxxxxxxxx; rjw@xxxxxxxxxxxxx; > andriy.shevchenko@xxxxxxxxxxxxxxx; lenb@xxxxxxxxxx; michael.jamet@xxxxxxxxx; > yehezkel.bernat@xxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; linux- > pci@xxxxxxxxxxxxxxx; mika.westerberg@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v2 1/5] PCI: Make sure all bridges reserve at least one bus > number > > On Fri, Feb 23, 2018 at 12:52:18AM +0000, Mario.Limonciello@xxxxxxxx wrote: > > On Feb 22, 2018 18:27, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > On Thu, Feb 15, 2018 at 05:39:55PM +0300, Mika Westerberg wrote: > > > > When distributing extra buses between hotplug bridges we need to make > > > > sure each bridge reserve at least one bus number, even if there is > > > > currently nothing connected to it. For instance ACPI hotplug may bring > > > > in additional devices to non-hotplug bridges later on. To make sure we > > > > don't run out of bus numbers for non-hotplug bridges reserve one bus > > > > number for them upfront before distributing buses for hotplug bridges. > > > > > > > > Fixes: 1c02ea810065 ("PCI: Distribute available buses to hotplug-capable > bridges") > > > > Reported-by: Mario Limonciello <mario.limonciello@xxxxxxxx> > > > > > > Is there a bugzilla or email URL we can include here? > > > > Sorry it was private communication that I believe Mika is referring to in Reported- > By here. > > > > You can remove the tag if you think it's inappropriate for this commit. > > I like to give credit whenever possible, so I wouldn't necessarily > remove the Reported-by. > > But it would be very useful to also have a URL to something with more > details, e.g., what sort of failure the user would observe, dmesg > logs, PCI topology, etc. > > This information can certainly be redacted to remove any proprietary > things that can't be made public. Usually that isn't of interest to > structural issues like this anyway. It was a result of a very long communication chain, but I think I pulled out the relevant details here if you would like a URL to include: https://gist.github.com/superm1/100a2ed20449f684ebb84c392e35dbed Thank you. > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > > > Cc: stable@xxxxxxxxxxxxxxx > > > > --- > > > > drivers/pci/probe.c | 11 ++++++++--- > > > > 1 file changed, 8 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > > > > index ef5377438a1e..6cefd47556e3 100644 > > > > --- a/drivers/pci/probe.c > > > > +++ b/drivers/pci/probe.c > > > > @@ -2561,7 +2561,10 @@ static unsigned int > pci_scan_child_bus_extend(struct pci_bus *bus, > > > > for_each_pci_bridge(dev, bus) { > > > > cmax = max; > > > > max = pci_scan_bridge_extend(bus, dev, max, 0, 0); > > > > - used_buses += cmax - max; > > > > + /* Reserve one bus for each bridge */ > > > > + used_buses++; > > > > + if (cmax - max > 1) > > > > + used_buses += cmax - max - 1; > > > > } > > > > > > > > /* Scan bridges that need to be reconfigured */ > > > > @@ -2584,12 +2587,14 @@ static unsigned int > pci_scan_child_bus_extend(struct pci_bus *bus, > > > > * bridges if any. > > > > */ > > > > buses = available_buses / hotplug_bridges; > > > > - buses = min(buses, available_buses - used_buses); > > > > + buses = min(buses, available_buses - used_buses + 1); > > > > } > > > > > > > > cmax = max; > > > > max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1); > > > > - used_buses += max - cmax; > > > > + /* One bus is already accounted so don't add it again */ > > > > + if (max - cmax > 1) > > > > + used_buses += max - cmax - 1; > > > > } > > > > > > > > /* > > > > -- > > > > 2.15.1 > > > > > > > > -- > > > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > > > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > >
