IB/qib: Default some module parameters optimally

Minimize the need for users to have to set module parameters to get
good performance.

The following two parameters are changed:
 - rcvhdrcnt to twice the rcvegrcnt
 - pcie_caps=0x51

The rcvhdrcnt at twice the egrcount allows the preemptive NAK code
during reception to function in 100% of the cases rather than a sender
jiffies-based timeout.

The pcie_caps default of 0x51 will set the proposed MaxPayload and
MaxReceiveReqest to 256 and 4096 respectively.  The capabilities on
the root complex will be used to limit those values.
Reviewed-by: Ram Vepa <ram.vepa@qlogic.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/qib/qib_iba7322.c

@@ -3603,7 +3603,7 @@ static void qib_7322_config_ctxts(struct qib_devdata *dd)
 	if (qib_rcvhdrcnt)
 		dd->rcvhdrcnt = max(dd->cspec->rcvegrcnt, qib_rcvhdrcnt);
 	else
-		dd->rcvhdrcnt = max(dd->cspec->rcvegrcnt,
+		dd->rcvhdrcnt = 2 * max(dd->cspec->rcvegrcnt,
 				    dd->num_pports > 1 ? 1024U : 2048U);
 }
 

drivers/infiniband/hw/qib/qib_pcie.c

@@ -560,9 +560,9 @@ static int qib_tune_pcie_coalesce(struct qib_devdata *dd)
  * BIOS may not set PCIe bus-utilization parameters for best performance.
  * Check and optionally adjust them to maximize our throughput.
  */
-static int qib_pcie_caps;
+static int qib_pcie_caps = 0x51;
 module_param_named(pcie_caps, qib_pcie_caps, int, S_IRUGO);
-MODULE_PARM_DESC(pcie_caps, "Max PCIe tuning: Payload (4lsb), ReadReq (D4..7)");
+MODULE_PARM_DESC(pcie_caps, "Max PCIe tuning: Payload (0..3), ReadReq (4..7)");
 
 static int qib_tune_pcie_caps(struct qib_devdata *dd)
 {