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Re: kern/46696: uhub disables port where USB keyboard attached
The following reply was made to PR kern/46696; it has been noted by GNATS.
From: Andreas Gustafsson <gson%gson.org@localhost>
To: gnats-bugs%netbsd.org@localhost, mishka%NetBSD.org@localhost,
Subject: Re: kern/46696: uhub disables port where USB keyboard attached
Date: Sat, 15 Sep 2012 16:40:05 +0300
I have now identified the commit where kern/46696 appeared (on my
machine, at least) by means of a semi-automated binary search. It was
src/sys/dev/usb/usb_subr.c 1.172, committed by Matthias more than two
date: 2010/07/20 20:56:06; author: drochner; state: Exp; lines: +43 -14
another iteration in the eternal device enumeration struggle:
use a request of 64 bytes for the initial device descriptor fetch.
This is what windows does, and I've seen USB device firmware which
really depends on this. (sends 8 bytes if 64 are requested and
the full descriptor which is more than NetBSD's USB_MAX_IPACKET
otherwise) This is the world...
For testing, I have prepared a patch which effectively reverts this commit:
Mike, can you try this patch and see if it fixes the problem for you?
Matthias, can you identify the USB device that prompted the above
commit? And if it is a full-speed device, would it be possible
to use the 64-byte request size for full-speed devices but not
Andreas Gustafsson, gson%gson.org@localhost
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