Re: kern/46696: uhub disables port where USB keyboard attached

[Andreas Gustafsson <gson%gson.org@localhost>]

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, 
drochner%NetBSD.org@localhost
Cc: 
Subject: Re: kern/46696: uhub disables port where USB keyboard attached
Date: Sat, 15 Sep 2012 16:40:05 +0300

 Mike, Matthias,
 
 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
 years ago:
 
   revision 1.172
   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:
 
   http://www.gson.org/netbsd/bugs/46696/usb.patch
 
 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
 low-speed ones?
 -- 
 Andreas Gustafsson, gson%gson.org@localhost