usb/181987: USB isochronous transfer of the USB driver (Mentor Graphics OTG: musb_otg) is not working.

[SAITOU Toshihide]

>Number:         181987
>Category:       usb
>Synopsis:       USB isochronous transfer of the USB driver (Mentor Graphics OTG: musb_otg) is not working.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-usb
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Sep 10 11:10:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     SAITOU Toshihide
>Release:        FreeBSD 10.0-CURRENT
>Organization:
>Environment:
FreeBSD bbb 10.0-CURRENT FreeBSD 10.0-CURRENT #1: Mon Sep  9 23:34:15 JST 2013     toshi at fbsd:/usr/obj/arm.armv6/usr/src/sys/BEAGLEBONE  arm

>Description:
The patch attached is somewhat fixed the problem for the
LOGICOOL C920 but still most UVC devices are not working.

My guess is that the not working device requires three
transactions per *microframe* for the data transfer rate as
the video streaming but the current driver performs one
transaction per microframe. The following page imply the
existence of the undocumented setting to perform so.
http://e2e.ti.com/support/embedded/wince/f/353/t/68966.aspx

>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: