[U-Boot] [PATCH v5 3/4] usb: Don't reset the USB hub a 2nd time

[Bin Meng]

On Tue, Mar 15, 2016 at 8:59 PM, Stefan Roese <sr at denx.de> wrote:
> Debugging has shown, that all USB hubs are being reset 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. Resulting in faster USB
> scan time. Here the current numbers:
>
> Without this patch:
> => time usb start
> starting USB...
> USB0:   USB EHCI 1.00
> scanning bus 0 for devices... 9 USB Device(s) found
>
> time: 24.003 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: 20.392 seconds
>
> So ~3.6 seconds of USB scanning time reduction.
>
> Signed-off-by: Stefan Roese <sr at denx.de>
> Cc: Simon Glass <sjg at chromium.org>
> Acked-by: Hans de Goede <hdegoede at redhat.com>
> Tested-by: Stephen Warren <swarren at nvidia.com>
> Cc: Marek Vasut <marex at denx.de>
>
> ---
>
> Changes in v5: None
> Changes in v4:
> - Minor rewording / fixes of the commit text
> - Add Acked-by from Hans
>
> Changes in v3: None
> Changes in v2:
> - Make this change unconditional
> - Add Tested-by from Stephen
>
>  common/usb.c | 13 +------------
>  1 file changed, 1 insertion(+), 12 deletions(-)
>

Tested-by: Bin Meng <bmeng.cn at gmail.com>