On Wed, May 02, 2018 at 12:57:31PM +0000, Gilles Buloz wrote: > Hi Bjorn, > See attached patch (tested ok this morning) This looks good. Minor comments below. I can fix minor things myself, but I do need a signed-off-by from you before applying (see https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst) Please add a changelog, too, and include the patch inline (as opposed to as an attachment) if possible. > --- include/linux/pci.h.orig 2018-03-26 16:51:18.050000000 +0000 > +++ include/linux/pci.h 2018-04-30 18:29:14.140000000 +0000 > @@ -193,6 +193,7 @@ > enum pci_bus_flags { > PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1, > PCI_BUS_FLAGS_NO_MMRBC = (__force pci_bus_flags_t) 2, > + PCI_BUS_FLAGS_NO_EXTCFG = (__force pci_bus_flags_t) 4, Best if you can rebase this to v4.17-rc1. > }; > > /* These values come from the PCI Express Spec */ > --- drivers/pci/probe.c.orig 2018-01-22 09:29:52.000000000 +0000 > +++ drivers/pci/probe.c 2018-05-02 13:44:35.530000000 +0000 > @@ -664,6 +664,23 @@ > } > } > > +static bool pci_bridge_child_bus_ext_cfg_accessible(struct pci_dev *bridge) > +{ > + int pos; > + u32 status; > + > + if (!pci_is_pcie(bridge) || /* PCI/PCI bridge */ > + (pci_pcie_type(bridge) == PCI_EXP_TYPE_PCIE_BRIDGE) || /* PCIe/PCI bridge in forward mode */ > + (pci_pcie_type(bridge) == PCI_EXP_TYPE_PCI_BRIDGE)) { /* PCIe/PCI bridge in reverse mode */ > + pos = pci_find_capability(bridge, PCI_CAP_ID_PCIX); > + if (pos) > + pci_read_config_dword(bridge, pos + PCI_X_STATUS, &status); > + return pos && (status & (PCI_X_STATUS_266MHZ | PCI_X_STATUS_533MHZ)); > + } Please arrange this so everything fits in 80 columns. If you can split it into several simpler "if" statements rather than one with a complicated expression, that would also be good. > + > + return true; > +} > + > static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent, > struct pci_dev *bridge, int busnr) > { > @@ -725,6 +742,19 @@ > /* Create legacy_io and legacy_mem files for this bus */ > pci_create_legacy_files(child); > > + /* > + * if bus_flags inherited from parent bus do not already report lack of extended config > + * space support, check if supported by child bus by checking its parent bridge > + */ Wrap to fit in 80 columns. > + if (bridge && !(child->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG)) { The double negative makes this a little bit hard to read. Maybe it could be improved by reversing the sense of something? > + if (!pci_bridge_child_bus_ext_cfg_accessible(bridge)) { > + child->bus_flags |= PCI_BUS_FLAGS_NO_EXTCFG; > + dev_info(&child->dev, "extended config space not accessible due to parent bridge\n"); In v4.17-rc1, there's a pci_info() that should work here (instead of dev_info()). > + } > + } else { > + dev_info(&child->dev, "extended config space not accessible due to parent bus\n"); > + } > + > return child; > } > > @@ -1084,6 +1114,9 @@ > u32 status; > u16 class; > > + if (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG) > + return PCI_CFG_SPACE_SIZE; > + > class = dev->class >> 8; > if (class == PCI_CLASS_BRIDGE_HOST) > return pci_cfg_space_size_ext(dev);
