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 P. -----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
