Multiple Commands in USB-2 - UAS

Madhukar madhukar.gubba at gmail.com
Thu Aug 20 06:36:44 PDT 2009


* From the T10 Reflector (t10 at t10.org), posted by:
* Madhukar <madhukar.gubba at gmail.com>
*
Thank You for the replies.
I have one last question. If USB2.0 supports multiple command
processing, here is the scenario where I am getting problem
If “UAS initiator port” issues a READ command followed by WRITE
command, the SENSE_IU (of READ command) data buffer is getting filled
with the data of WRITE_READY issued for WRITE command by the “UAS
target port” at the HCD level.
This is happening because when UAS Initiator port is expecting
SENSE_IU (for READ Command) the UAS target port sent WRITE_READY (for
WRITE Command) to UAS Initiator port on same pipe.
I am assuming that the READ and WRITE can be processed simultaneously
at “UAS target port” and there is no verification of Tag values of
request and response at HCD level in USB 2.0.
Thanks and Regards,
madhukar
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