[U-Boot] [PATCH 2/6] usb: Remove 200 ms delay in usb_hub_port_connect_change()

Stephen Warren
2016-03-11T00:06:35Z

On 03/10/2016 08:50 AM, Stefan Roese wrote:
> 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: 24.811 seconds
>
> So ~3.5 seconds of USB scanning time reduction.
>
> These mdelay calls are removed if CONFIG_USB_FAST_SCAN is defined. They
> are not removed per default yet. It would be good to test with this
> option enabled on many other boards. And once we have a good testing
> base we can decide to remove these delays completely, including this
> macro.

This patch,
Tested-by: Stephen Warren <swarren@nvidia.com>