From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hans de Goede <hdegoede@redhat.com>
Date: Thu, 10 Mar 2016 19:55:34 +0100
Subject: [U-Boot] [PATCH 2/6] usb: Remove 200 ms delay in
 usb_hub_port_connect_change()
In-Reply-To: <1457625012-1268-3-git-send-email-sr@denx.de>
References: <1457625012-1268-1-git-send-email-sr@denx.de>
 <1457625012-1268-3-git-send-email-sr@denx.de>
Message-ID: <56E1C326.90708@redhat.com>
List-Id: <u-boot.lists.denx.de>
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To: u-boot@lists.denx.de

Hi,

On 10-03-16 16:50, 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.

There indeed is no reason at all to delay before the reset and the kernel
does not wait with checking the USB_PORT_STAT_SPEED_MASK once the
reset completes, so I see no reason why we should:

Acked-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans

>
> Signed-off-by: Stefan Roese <sr@denx.de>
> Cc: Simon Glass <sjg@chromium.org>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Stephen Warren <swarren@nvidia.com>
> Cc: Marek Vasut <marex@denx.de>
> ---
>
>   common/usb_hub.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/common/usb_hub.c b/common/usb_hub.c
> index 10fdd3c..660f4f4 100644
> --- a/common/usb_hub.c
> +++ b/common/usb_hub.c
> @@ -275,7 +275,9 @@ int usb_hub_port_connect_change(struct usb_device *dev, int port)
>   		if (!(portstatus & USB_PORT_STAT_CONNECTION))
>   			return -ENOTCONN;
>   	}
> +#if !defined(CONFIG_USB_FAST_SCAN)
>   	mdelay(200);
> +#endif
>
>   	/* Reset the port */
>   	ret = legacy_hub_port_reset(dev, port, &portstatus);
> @@ -285,7 +287,9 @@ int usb_hub_port_connect_change(struct usb_device *dev, int port)
>   		return ret;
>   	}
>
> +#if !defined(CONFIG_USB_FAST_SCAN)
>   	mdelay(200);
> +#endif
>
>   	switch (portstatus & USB_PORT_STAT_SPEED_MASK) {
>   	case USB_PORT_STAT_SUPER_SPEED:
>