On Mon, Jan 12, 2015 at 11:31:09PM +0100, Kjetil Oftedal wrote: > Hi, > > Am I missing something or is this just code to get the the resource > subsystem to accept the bus resources, not caring if the resources are > actually usable? PCI BARs usually have a given size for a reason?
Hi Kjetil, This isn't for regular PCI BARs (Yinghai did apply it to some regular BARs in the v1 patches, but I think that was a mistake). This is for scenarios like this: pci_bus 0000:00: root bus resource [mem 0xc0000000-0xffffffff] pci 0000:00:01.0: bridge window [mem 0xbdf00000-0xddefffff 64bit pref] pci 0000:01:00.0: reg 0x10: [mem 0xc0000000-0xcfffffff pref] The 00:01.0 window is illegal: it starts before the host bridge window, so we have to assume the [0xbdf00000-0xbfffffff] region is inaccessible. We can make it legal by clipping it to [mem 0xc0000000-0xddefffff 64bit pref]. Linux should never assign an illegal bridge window like this, but some firmware does, and the idea is to make a minimal change (clip the window) before resorting to the big hammer of reassigning resources from scratch. Bjorn > On 12/01/2015, Yinghai Lu <[email protected]> wrote: > > Some bios put range that is not fully coverred by root bus resources. > > Try to clip them and update them in pci bridge bars. > > > > We'd like to fix other arches instead of just x86. > > > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=85491 > > Reported-by: Marek Kordik <[email protected]> > > Fixes: 5b28541552ef ("PCI: Restrict 64-bit prefetchable bridge windows to > > 64-bit resources") > > Signed-off-by: Yinghai Lu <[email protected]> > > Cc: "David S. Miller" <[email protected]> > > Cc: Paul Gortmaker <[email protected]> > > Cc: Yijing Wang <[email protected]> > > Cc: Sam Ravnborg <[email protected]> > > Cc: [email protected] > > --- > > arch/sparc/kernel/pci.c | 20 +++++++++++++++++++- > > 1 file changed, 19 insertions(+), 1 deletion(-) > > > > diff --git a/arch/sparc/kernel/pci.c b/arch/sparc/kernel/pci.c > > index b36365f..0e391e5 100644 > > --- a/arch/sparc/kernel/pci.c > > +++ b/arch/sparc/kernel/pci.c > > @@ -623,6 +623,7 @@ static void pci_claim_bus_resources(struct pci_bus > > *bus) > > struct pci_dev *dev; > > > > list_for_each_entry(dev, &bus->devices, bus_list) { > > + bool changed = false; > > int i; > > > > for (i = 0; i < PCI_NUM_RESOURCES; i++) { > > @@ -639,8 +640,25 @@ static void pci_claim_bus_resources(struct pci_bus > > *bus) > > (unsigned long long)r->end, > > (unsigned int)r->flags); > > > > - pci_claim_resource(dev, i); > > + if (pci_claim_resource(dev, i) >= 0) > > + continue; > > + > > + if (dev->subordinate && > > + i >= PCI_BRIDGE_RESOURCES && > > + i < PCI_NUM_RESOURCES && > > + (dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && > > + pci_bus_clip_resource(dev, r)) { > > + changed = true; > > + pci_claim_resource(dev, i); > > + } else if (i < PCI_BRIDGE_RESOURCES && > > + i != PCI_ROM_RESOURCE && > > + pci_bus_clip_resource(dev, r)) { > > + pci_update_resource(dev, i); > > + pci_claim_resource(dev, i); > > + } > > } > > + if (changed) > > + pci_setup_bridge(dev->subordinate); > > } > > > > list_for_each_entry(child_bus, &bus->children, node) > > -- > > 1.8.4.5 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe sparclinux" in > > the body of a message to [email protected] > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
