From: Stefan Roese <sr@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 5/6] usb: Don't reset the USB hub a 2nd time
Date: Fri, 11 Mar 2016 07:43:07 +0100 [thread overview]
Message-ID: <56E268FB.6070005@denx.de> (raw)
In-Reply-To: <56E1C755.70405@redhat.com>
On 10.03.2016 20:13, Hans de Goede wrote:
> Hi,
>
> On 10-03-16 16:50, 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.
>
> I see no reason to make the removal conditional, I believe that
> this is some relic workaround for likely long fixed bugs and
> we should just remove it completely (for v2016.07).
Thanks. I'll make this change unconditional in the next patch version
as well.
Thanks,
Stefan
next prev parent reply other threads:[~2016-03-11 6:43 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
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 [this message]
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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