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From: Stephen Warren <swarren@wwwdotorg.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 2/3] ARM: Tegra: USB: Add driver support for Tegra30/Tegra114
Date: Fri, 03 May 2013 08:46:01 -0600	[thread overview]
Message-ID: <5183CDA9.8040100@wwwdotorg.org> (raw)
In-Reply-To: <1367578411.1302.6.camel@jilin-desktop>

On 05/03/2013 04:53 AM, Jim Lin wrote:
> On Fri, 2013-05-03 at 03:29 +0800, Stephen Warren wrote:
>> On 04/29/2013 03:21 AM, Jim Lin wrote:
>>> Tegra30 and Tegra114 are compatible except
>>> 1. T30 takes 55 ms to finish Port Reset. T114 takes
>>>    50 ms.
>>
>> Is that 55-vs-50 some aspect of the HW specification itself, or the
>> overall result of multiple separate delays? I ask because the statement
>> that one piece of HW differs from another only in a delay, especially
>> where that delay is enormous in HW terms, seem very unusual.
> 
> 50 ms comes from USB 2.0 specification for root port.
> 55 ms comes from T30 Technical Reference Manual.

OK, I see this value is indeed in the TRM, so I guess the code is OK.

> Overall result of multiple separate delays.

That doesn't seem true though; the TRM simply documents a single 55ms
delay, not a set of delays that add up to 55ms.

  reply	other threads:[~2013-05-03 14:46 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-29  9:21 [U-Boot] [PATCH 0/3] Tegra: USB: EHCI: add Tegra30 compatible support Jim Lin
2013-04-29  9:21 ` [U-Boot] [PATCH 1/3] ARM: Tegra: FDT: Add USB support for T20/T30/T114 Jim Lin
2013-05-02 19:10   ` Stephen Warren
2013-05-03 11:07     ` Jim Lin
2013-05-03 14:43       ` Stephen Warren
2013-05-03 11:48     ` Venu Byravarasu
2013-04-29  9:21 ` [U-Boot] [PATCH 2/3] ARM: Tegra: USB: Add driver support for Tegra30/Tegra114 Jim Lin
2013-04-29 23:46   ` Marek Vasut
2013-04-30 16:21     ` Tom Warren
2013-04-30 17:09       ` Marek Vasut
2013-04-30 17:20       ` Tom Rini
2013-05-01 16:16         ` Tom Warren
2013-05-01 16:45           ` Tom Rini
2013-05-01 19:33             ` Marek Vasut
2013-05-01 23:20               ` Tom Warren
2013-05-01 23:23                 ` Tom Warren
2013-05-02  9:50               ` Jim Lin
2013-05-02 11:38                 ` Marek Vasut
2013-05-02 15:38                   ` Tom Warren
2013-05-02 19:29   ` Stephen Warren
2013-05-03 10:53     ` Jim Lin
2013-05-03 14:46       ` Stephen Warren [this message]
2013-04-29  9:21 ` [U-Boot] [PATCH 3/3] Tegra: Config: Enable Tegra30/Tegra114 USB function Jim Lin
2013-05-02 19:30   ` Stephen Warren
2013-05-03 15:02 ` [U-Boot] [PATCH 0/3] Tegra: USB: EHCI: add Tegra30 compatible support Stephen Warren
2013-05-08 16:11   ` Stephen Warren

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