linux-kernel - Re: [linux-usb-devel] ThinkPad T41

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 12 Jun 2007 00:42:28 +0200
From:	Robert de Rooy <robert.de.rooy@...il.com>
To:	Alan Stern <stern@...land.harvard.edu>
CC:	Jiri Kosina <jikos@...os.cz>, Greg KH <greg@...ah.com>,
	Joel.Becker@...cle.com,
	USB development list <linux-usb-devel@...ts.sourceforge.net>,
	Kernel development list <linux-kernel@...r.kernel.org>
Subject: Re: [linux-usb-devel] ThinkPad T41 - Strange USB 2.0 behaviour

Alan Stern wrote:
> Okay.  It's clear that you've got a hardware problem of some sort.  
> Hard to say what it is, but evidently the EHCI controller thinks that 
> the device is repeatedly being unplugged and replugged.
>
> Anyway, this isn't a problem of recognizing that a single device is
> having problems.  In fact the computer has no way of knowing that a
> single device is involved; all it knows is that _something_ gets
> plugged into the port and then removed.  There's no way to tell if it's 
> the same _something_ from one iteration to the next.
>
> You can manually force the port to run at full speed instead of high 
> speed as follows:
>
> 	echo '4' >/sys/class/usb_host/usb_host4/companion
>
> The "companion" attribute file contains a list of ports which are 
> permanently set to be handled by the EHCI's companion controller.  To 
> return to high-speed operation, use '-4' instead of '4' above.  This 
> might or might not solve your problem -- the hardware bug might cause 
> the port to return automatically to high-speed regardless.
>
> Let me know what happens.
>
> Alan Stern

Yes that works.
I tried to plug and unplug the device repeatedly and each time it came 
up in full-speed mode.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/