Some root ports may return the actual device id returned by the endpoint, instead of faking up a synthetic id (0xFFFF) as specified by the PCIe spec (sec 2.3.2). We have seen such broken devices in the past that match this behaviour: (Ref: https://lkml.org/lkml/2007/11/1/198)
To take care of the same, CRS was disabled then, however, we want to enable CRS now (https://lkml.org/lkml/2014/9/2/509), but still do not want to break such devices. Thus check only against the (vendor id == 1) and ignore the device id. Signed-off-by: Rajat Jain <[email protected]> Signed-off-by: Rajat Jain <[email protected]> Signed-off-by: Guenter Roeck <[email protected]> --- drivers/pci/probe.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 3c4c35c..0076a9b 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1305,8 +1305,13 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l, *l == 0x0000ffff || *l == 0xffff0000) return false; - /* Configuration request Retry Status */ - while (*l == 0xffff0001) { + /* + * Configuration request Retry Status. Note that some root ports + * are broken and may return actual device ID instead of a synthetic ID + * (0xFFFF) to be faked as per the PCIe spec. Hence ignore the device ID + * and only check for (vendor id == 1) + */ + while (*l & 0xffff == 0x0001) { if (!crs_timeout) return false; -- 1.7.9.5 -- 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/
