On Wed, Apr 25, 2012 at 11:56 AM, Prarit Bhargava <prarit@xxxxxxxxxx> wrote: > This patch died on the vine after some reviews. The last version of this > patch was posted here: > > http://marc.info/?l=linux-pci&m=132148921701034&w=2 Sorry this fell through the cracks. I fiddled with it some more and tried to understand the topology more clearly. I'll post it right now; please take a look and tell me where I screwed up :) Bjorn > -----8<----- > > pci: Workaround Stratus broken PCIE hierarchy > > Stratus systems have a hierarchy that includes a PCIE Downstream bridge > connected to a PCIE Upstream bridge and a PCI Downstream bridge. The > system boots with this wrong hierarchy into a crippled mode (USB doesn't > work, network doesn't work ...). Avoiding the Downstream bridge check in > only_one_child() causes all the bridges to be enumerated and the system to > function properly. > > Unfortunately this hardware is currently available so we should at least > keep it functional. > > [v2] > - ddutile@xxxxxxxxxx requested drivers/pci/quirks.c code > - matthew@xxxxxx requested that dmi_name_in_vendors() be called only once with a static var check > - added a kernel parameter to enable scanning of all PCIE devices. > > [v3] > - matthew@xxxxxx requested a clean up of is_broken_pcie_port( > - eike-kernel@xxxxxxxxx requested a clean up of the printk level and message > > [v4] > - ddutile pointed out a logic error in is_broken_pcie_port. It was no longer > being called only once on failure. > > Cc: ddutile@xxxxxxxxxx > Cc: matthew@xxxxxx > Cc: eike-kernel@xxxxxxxxx > Cc: bhelgaas@xxxxxxxxxx > Cc: jim.paradis@xxxxxxxxxxx > Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> > --- > Documentation/kernel-parameters.txt | 1 + > drivers/pci/pci.c | 3 +++ > drivers/pci/pci.h | 5 +++++ > drivers/pci/probe.c | 9 +++++++-- > drivers/pci/quirks.c | 18 ++++++++++++++++++ > include/linux/pci.h | 2 ++ > 6 files changed, 36 insertions(+), 2 deletions(-) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index c1601e5..1284b2e 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -2161,6 +2161,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > on: Turn realloc on > realloc same as realloc=on > noari do not use PCIe ARI. > + pcie_scan_all Scan all possible PCIE devices. > > pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power > Management. > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 111569c..82e89ad 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -3893,6 +3893,9 @@ static int __init pci_setup(char *str) > pcie_bus_config = PCIE_BUS_PERFORMANCE; > } else if (!strncmp(str, "pcie_bus_peer2peer", 18)) { > pcie_bus_config = PCIE_BUS_PEER2PEER; > + } else if (!strncmp(str, "pcie_scan_all", 13)) { > + printk(KERN_INFO HW_ERR "PCIE: User request scan of all PCIE devices. Your PCIE hardware is broken if you require this to boot.\n"); > + pcie_scan_all = 1; > } else { > printk(KERN_ERR "PCI: Unknown option `%s'\n", > str); > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index e494347..a1baad2 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -319,11 +319,16 @@ struct pci_dev_reset_methods { > > #ifdef CONFIG_PCI_QUIRKS > extern int pci_dev_specific_reset(struct pci_dev *dev, int probe); > +extern int is_broken_pcie_port(void); > #else > static inline int pci_dev_specific_reset(struct pci_dev *dev, int probe) > { > return -ENOTTY; > } > +static inline int is_broken_pcie_port(void) > +{ > + return 0; > +} > #endif > > #endif /* DRIVERS_PCI_H */ > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 5e1ca3c..07c6245 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1392,13 +1392,18 @@ static unsigned no_next_fn(struct pci_dev *dev, unsigned fn) > return 0; > } > > +int pcie_scan_all; /* set via pci=pcie_scan_all */ > static int only_one_child(struct pci_bus *bus) > { > struct pci_dev *parent = bus->self; > + if (pcie_scan_all) > + return 0; > if (!parent || !pci_is_pcie(parent)) > return 0; > - if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT || > - parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM) > + if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT) > + return 1; > + if (parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM && > + !is_broken_pcie_port()) > return 1; > return 0; > } > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index 4bf7102..d60e99c 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -3109,3 +3109,21 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe) > > return -ENOTTY; > } > + > +static int is_broken_pcie_port_called; > +int is_broken_pcie_port(void) > +{ > + if (is_broken_pcie_port_called) > + return pcie_scan_all; > + /* > + * Stratus/NEC ftServer systems have a broken PCIE hierarchy in which > + * one upstream and one downstream port are plugged into a downstream > + * port. Avoiding the downstream port check in only_one_child() results > + * in a functional system. > + */ > + if (dmi_name_in_vendors("ftServer")) > + pcie_scan_all = 1; > + > + is_broken_pcie_port_called = 1; > + return pcie_scan_all; > +} > diff --git a/include/linux/pci.h b/include/linux/pci.h > index e444f5b..bb3daa7 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1720,5 +1720,7 @@ static inline struct eeh_dev *pci_dev_to_eeh_dev(struct pci_dev *pdev) > */ > struct pci_dev *pci_find_upstream_pcie_bridge(struct pci_dev *pdev); > > +/* set via pci=pcie_scan_all in order to enumerate all possible PCIE busses */ > +extern int pcie_scan_all; > #endif /* __KERNEL__ */ > #endif /* LINUX_PCI_H */ > -- > 1.7.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
