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List:       libusb-devel
Subject:    Re: [libusb] Clarification on libusb_handle_events
From:       Pradeepa Senanayake <pradeepa.kck () gmail ! com>
Date:       2015-09-29 9:52:26
Message-ID: CA+1tQ70Aju+RFpP8v=FA-1RUW5RdTUkdmR7b_8BZ1x-4aQxLFQ () mail ! gmail ! com
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[Attachment #2 (multipart/alternative)]


​

On Sat, Sep 26, 2015 at 9:00 PM, Alan Stern <stern@rowland.harvard.edu>
wrote:

Does the SABRE SD development board use an EHCI USB controller with a
> root-hub Transaction Translator?  Some versions of some of the drivers
> had a bug that affected full-speed isochronous transfers in EHCI; not
> all of the scheduled transfers would take place during each frame.
>
> (On the other hand, if you were affected by this bug the symptoms would
> be different.  You would lose data in every frame, not just at the
> start of a transfer.)
>
>
​Also, if this is the case I think I will lose data from both endpoints.​


>
> Yes, the setup has been completed.  But the transfers won't start right
> away; the host controller has a latency on the order of 1 ms.
>
>
​Thank you for the information.​

Best Regards,
Pradeepa Senanayake.​

[Attachment #5 (text/html)]

<div dir="ltr"><div class="gmail_default" style="color:rgb(11,83,148)"><br></div><div \
class="gmail_extra"><div class="gmail_default" style="color:rgb(11,83,148)">​</div> \
<br><div class="gmail_quote">On Sat, Sep 26, 2015 at 9:00 PM, Alan Stern <span \
dir="ltr">&lt;<a href="mailto:stern@rowland.harvard.edu" \
target="_blank">stern@rowland.harvard.edu</a>&gt;</span> wrote:</div><div \
class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px \
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Does \
the SABRE SD development board use an EHCI USB controller with a<br> root-hub \
Transaction Translator?   Some versions of some of the drivers<br> had a bug that \
affected full-speed isochronous transfers in EHCI; not<br> all of the scheduled \
transfers would take place during each frame.<br> <br>
(On the other hand, if you were affected by this bug the symptoms would<br>
be different.   You would lose data in every frame, not just at the<br>
start of a transfer.)<br>
<span class=""><br>
</span></blockquote><div><br></div><div><div class="gmail_default" \
style="color:rgb(11,83,148)">​Also, if this is the case I think I will lose data \
from both endpoints.​</div></div><div>  </div><blockquote class="gmail_quote" \
style="margin:0px 0px 0px \
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span \
class=""> <br>
</span>Yes, the setup has been completed.   But the transfers won&#39;t start \
right<br> away; the host controller has a latency on the order of 1 ms.<br>
<span class=""><font \
color="#888888"><br></font></span></blockquote><div><br></div><div \
class="gmail_default" style="color:rgb(11,83,148)">​Thank you for the \
information.​</div><div><br></div></div></div><div class="gmail_extra"><div><div \
class="gmail_signature"><div dir="ltr"><div style="font-family:arial"><font \
color="#0b5394">Best Regards,</font></div></div></div></div><div \
class="gmail_default" style="color:rgb(11,83,148)"><span \
style="font-family:arial">Pradeepa Senanayake.</span>​</div><br></div></div>



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