From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH V2] ush: ehci: initialize altnext pointers in QH
Date: Sat, 8 Feb 2014 15:01:11 +0100 [thread overview]
Message-ID: <201402081501.11120.marex@denx.de> (raw)
In-Reply-To: <1391792030-8457-1-git-send-email-swarren@wwwdotorg.org>
On Friday, February 07, 2014 at 05:53:50 PM, Stephen Warren wrote:
> From: Stephen Warren <swarren@nvidia.com>
>
> Section 4.10.2 "Advance Queue" of ehci-specification-for-usb.pdf
> specifies how an EHCI controller loads a new QTD for processing if the
> QH is not already marked as active. It states:
>
> =====
> If the field Bytes to Transfer is not zero and the T-bit in the Alternate
> Next qTD Pointer is set to zero, then the host controller uses the
> Alternate Next qTD Pointer. Otherwise, the host controller uses the Next
> qTD Pointer. If Next qTD Pointer?s T-bit is set to a one, then the host
> controller exits this state and uses the horizontal pointer to the next
> schedule data structure.
> =====
>
> Hence, we must ensure that the alternate next QTD pointer's T-bit
> (TERMINATE) is set, so the EHCI controller knows to use the next QTD
> pointer.
>
> Signed-off-by: Stephen Warren <swarren@nvidia.com>
Applied, thanks.
Best regards,
Marek Vasut
prev parent reply other threads:[~2014-02-08 14:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-07 16:53 [U-Boot] [PATCH V2] ush: ehci: initialize altnext pointers in QH Stephen Warren
2014-02-08 14:01 ` Marek Vasut [this message]
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