From: Stefan Roese <sr@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 2/6] usb: Remove 200 ms delay in usb_hub_port_connect_change()
Date: Fri, 11 Mar 2016 07:34:33 +0100 [thread overview]
Message-ID: <56E266F9.3010208@denx.de> (raw)
In-Reply-To: <56E1C326.90708@redhat.com>
On 10.03.2016 19:55, Hans de Goede wrote:
> 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>
Thanks. I'll remove the #if !defined(CONFIG_USB_FAST_SCAN) to make
this change default in the next patchset version.
Thanks,
Stefan
next prev parent reply other threads:[~2016-03-11 6:34 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-10 15:50 [U-Boot] [PATCH 0/6] usb: Reduce USB scanning time Stefan Roese
2016-03-10 15:50 ` [U-Boot] [PATCH 1/6] usb: legacy_hub_port_reset(): Speedup hub reset handling Stefan Roese
2016-03-10 18:51 ` Hans de Goede
2016-03-11 6:37 ` Stefan Roese
2016-03-11 0:06 ` Stephen Warren
2016-03-10 15:50 ` [U-Boot] [PATCH 2/6] usb: Remove 200 ms delay in usb_hub_port_connect_change() Stefan Roese
2016-03-10 18:55 ` Hans de Goede
2016-03-11 6:34 ` Stefan Roese [this message]
2016-03-11 6:35 ` Stefan Roese
2016-03-11 0:06 ` Stephen Warren
2016-03-10 15:50 ` [U-Boot] [PATCH 3/6] usb: Remove 1 second per port timeout in usb_hub_configure() Stefan Roese
2016-03-10 18:59 ` Hans de Goede
2016-03-10 15:50 ` [U-Boot] [PATCH 4/6] usb: usb_hub_power_on(): Use 100ms power-on delay instead of 1 sec (optionally) Stefan Roese
2016-03-10 19:12 ` Hans de Goede
2016-03-11 9:05 ` Stefan Roese
2016-03-11 10:13 ` Stefan Roese
2016-03-11 10:32 ` Hans de Goede
2016-03-11 10:42 ` Stefan Roese
2016-03-10 15:50 ` [U-Boot] [PATCH 5/6] usb: Don't reset the USB hub a 2nd time Stefan Roese
2016-03-10 19:13 ` Hans de Goede
2016-03-11 6:43 ` Stefan Roese
2016-03-11 0:07 ` Stephen Warren
2016-03-10 15:50 ` [U-Boot] [PATCH 6/6] usb: Implement static USB port configuration to speed up USB scanning Stefan Roese
2016-03-10 19:18 ` Hans de Goede
2016-03-11 15:08 ` Stefan Roese
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