Le 02/05/2018 15:26, Bjorn Helgaas a écrit : > 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); > . > OK I'm going to learn about signing (sorry this is my first "official" patch). I'll download kernel v4.17-rc1 and write the patch for it; however I hope I'll be able to test it on my platform without the freescale addons I have on 4.1.35, because I don't want to send an untested patch. For "if (bridge && !(child->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG))", I don't understand what you mean with "double negative", as I only have one "!" Do you think it's worth keeping the two dev_info() ? The code would be smaller without; however this may help to have it for debug. Maybe use _dbg instead of _info ?
