[U-Boot] [PATCH 5/6] usb: Don't reset the USB hub a 2nd time

Stephen Warren
2016-03-11T00:07:14Z

On 03/10/2016 08:50 AM, Stefan Roese wrote:
> Debugging has shown, that all USB hubs are being resetted twice while
> USB scanning. This introduces additional delays and makes USB scanning
> even more slow. Testing has shown that this 2nd USB hub reset doesn't
> seem to be necessary.
>
> This patch now removes this 2nd USB hub reset if CONFIG_USB_FAST_SCAN
> is defined. Resulting in faster USB scan time. Here the current
> number:
>
> Without this patch:
> => time usb start
> starting USB...
> USB0: USB EHCI 1.00
> scanning bus 0 for devices... 9 USB Device(s) found
>
> time: 6.319 seconds
>
> With this patch:
> => time usb start
> starting USB...
> USB0: USB EHCI 1.00
> scanning bus 0 for devices... 9 USB Device(s) found
>
> time: 3.777 seconds
>
> So ~2.5 seconds of USB scanning time reduction.
>
> Again, this 2nd reset is only removed if CONFIG_USB_FAST_SCAN is
> defined. Once more tests are done on multiple other platforms we
> can decide to remove this 2nd reset completely.

This patch, after modifying the patch to unconditionally remove the code
rather than only conditionally,
Tested-by: Stephen Warren <swarren@nvidia.com>

For the other patches I agree with Hans' comments.