MLK-9785-1 usb: host: ehci-hcd: enable park mode

Enable park mode will improve the performance a lot at USB ethernet use
case, but a little at USB mass storage use case, and it is not harm from
the tests. Below the performance comparison at imx6sl:

USB Ethernet (Mbps)
	Default			Enable Park
TX	192			262
RX	262			290

USB Mass Storage (MB/s)
Read	21.8			22.9
Write	19.5			22.8

This patch is used for freescale internal.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
(cherry picked from commit b2289a78958859cff37508e4db0314463f33c2e0)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 0630648..a36fded 100644 (file)
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -93,7 +93,7 @@ module_param (log2_irq_thresh, int, S_IRUGO);
 MODULE_PARM_DESC (log2_irq_thresh, "log2 IRQ latency, 1-64 microframes");
 
 /* initial park setting:  slower than hw default */
-static unsigned park = 0;
+static unsigned park = 3;
 module_param (park, uint, S_IRUGO);
 MODULE_PARM_DESC (park, "park setting; 1-3 back-to-back async packets");