[U-Boot] [PATCH v4 2/4] usb: Remove 200 ms delay in usb_hub_port_connect_change()

Stefan Roese
2016-03-15T09:46:44Z

This patch removes 2 mdelay(200) calls from usb_hub_port_connect_change().
These delays don't seem to be necessary. At least not in my tests. Here
the number for a custom x86 Bay Trail board (not in mainline yet) with
a quite large and complex USB hub infrastructure.

Without this patch:
starting USB...
USB0: USB EHCI 1.00
scanning bus 0 for devices... 9 USB Device(s) found

time: 28.415 seconds

With this patch:
starting USB...
USB0: USB EHCI 1.00
scanning bus 0 for devices... 9 USB Device(s) found

time: 24.003 seconds

So ~4.5 seconds of USB scanning time reduction.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Cc: Marek Vasut <marex@denx.de>

---

Changes in v4:
- Add Acked-by / Tested-by from Hans and Stephen

Changes in v3: None
Changes in v2:
- Make this change unconditional
- Add Acked-by / Tested-by from Hans and Stephen

common/usb_hub.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/common/usb_hub.c b/common/usb_hub.c
index 2089e20..d621f50 100644
--- a/common/usb_hub.c
+++ b/common/usb_hub.c
@@ -275,7 +275,6 @@ int usb_hub_port_connect_change(struct usb_device *dev, int port)
if (!(portstatus & USB_PORT_STAT_CONNECTION))
return -ENOTCONN;
}
- mdelay(200);

/* Reset the port */
ret = legacy_hub_port_reset(dev, port, &portstatus);
@@ -285,8 +284,6 @@ int usb_hub_port_connect_change(struct usb_device *dev, int port)
return ret;
}

- mdelay(200);
-
switch (portstatus & USB_PORT_STAT_SPEED_MASK) {
case USB_PORT_STAT_SUPER_SPEED:
speed = USB_SPEED_SUPER;
--
2.7.3