[PATCH 5.3 30/48] IB/hfi1: Ensure full Gen3 speed in a Gen4 system

From: Greg Kroah-Hartman
Date: Tue Nov 19 2019 - 00:22:03 EST

From: James Erwin <james.erwin@xxxxxxxxx>

commit a9c3c4c597704b3a1a2b9bef990e7d8a881f6533 upstream.

If an hfi1 card is inserted in a Gen4 systems, the driver will avoid the
gen3 speed bump and the card will operate at half speed.

This is because the driver avoids the gen3 speed bump when the parent bus
speed isn't identical to gen3, 8.0GT/s. This is not compatible with gen4
and newer speeds.

Fix by relaxing the test to explicitly look for the lower capability
speeds which inherently allows for gen4 and all future speeds.

Fixes: 7724105686e7 ("IB/hfi1: add driver files")
Link: https://lore.kernel.org/r/20191101192059.106248.1699.stgit@xxxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Reviewed-by: Kaike Wan <kaike.wan@xxxxxxxxx>
Signed-off-by: James Erwin <james.erwin@xxxxxxxxx>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/infiniband/hw/hfi1/pcie.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/hfi1/pcie.c
+++ b/drivers/infiniband/hw/hfi1/pcie.c
@@ -319,7 +319,9 @@ int pcie_speeds(struct hfi1_devdata *dd)
* bus->max_bus_speed is set from the bridge's linkcap Max Link Speed
- if (parent && dd->pcidev->bus->max_bus_speed != PCIE_SPEED_8_0GT) {
+ if (parent &&
+ (dd->pcidev->bus->max_bus_speed == PCIE_SPEED_2_5GT ||
+ dd->pcidev->bus->max_bus_speed == PCIE_SPEED_5_0GT)) {
dd_dev_info(dd, "Parent PCIe bridge does not support Gen3\n");
dd->link_gen3_capable = 0;