From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759142AbZCYQ6u (ORCPT ); Wed, 25 Mar 2009 12:58:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755266AbZCYQ6m (ORCPT ); Wed, 25 Mar 2009 12:58:42 -0400 Received: from clausfischer.com ([78.46.66.52]:48519 "EHLO clausfischer.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751909AbZCYQ6l (ORCPT ); Wed, 25 Mar 2009 12:58:41 -0400 X-Greylist: delayed 1433 seconds by postgrey-1.27 at vger.kernel.org; Wed, 25 Mar 2009 12:58:40 EDT Date: Wed, 25 Mar 2009 17:34:41 +0100 From: Claus Fischer To: linux-kernel@vger.kernel.org Subject: Irritating USB Flash Memory LED behaviour (usb_storage related?) Message-ID: <20090325163441.GA17166@clausfischer.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="/9DWx/yDrRhgMJTb" Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --/9DWx/yDrRhgMJTb Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Summary: Some new USB memory sticks will not stop blinking the LED. Behaviour varies across distributions and OS's. Any helpful hints appreciated. On a system that we use for mass erasure of USB sticks (64 sticks), based on Debian with automatical udev-handling of USB sticks disabled, we have a problem with a batch of new USB sticks: They will continue blinking for as long as they are plugged in, independent of data access. The sticks however stop blinking (as they should) on a SuSE based desktop system with the usual KDE software. They also stop blinking when attached to a Windows system. Good behaviour: *************** Previously, (good) USB sticks would behave like this: - blink while the usb_storage module identifies them and maps them to an SCSI device - then stop blinking - blink again while being formatted via our script - stop blinking after being unmounted Together with a visual program display, the blinking LED has always been a good indicator for operating personnel of the stick's status. Bad behaviour: ************** The new sticks will start blinking when the usb_storage module kicks in use, and continue blinking throughout idle phases, mounts, writes, umounts etc.; an eject command will change the blinking to a permanently lighted LED, but it will never go off. I'm at a loss looking for the reason of the continued blinking, and how to get rid of it (it's a large batch of sticks, and returning them is out of the question). Possible causes: - Kernel But: the "good" SuSE kernel 2.6.25 is between "bad" Debian 2.6.16 and "bad" Debian 2.6.26. Also, old USB sticks work fine with each machine. - Bad USB controller The new batch of sticks uses a different internal USB controller from old batches. But: Windows and SuSE work fine. - Interaction of KDE components with the USB stick that is missing on our batch formatting system. But: Why do old sticks work fine without such interaction? Questions: - I always thought that USB stick LEDs cannot be controlled by the operating system. They just indicates "write accesses". Is that correct? - If USB stick leds are not OS-accessible, why do the new sticks behave differently on different systems? - If USB stick leds are OS-accessible, has there been any change in policy of kernel/modules that leave them blinking? - Can anyone point me to information how SuSE/KDE control the blinking light, and how I can (write code to) let the LED react similarly on our Debian-based batch system? [ For various reasons beyond the scope of this mail, automatically mounting the sticks is out of the question. ] Any helpful hints, pointers to knowledge/information etc. are greatly appreciated. Best regards, Claus --=20 Claus Fischer http://www.clausfischer.com/ --/9DWx/yDrRhgMJTb Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iD8DBQFJyl0hm6yxRhwvRIsRAp94AJ0QRQC/dxUigkz1Rbipe5hTjdKykwCeKXcG 4Ou1yHq0l4E0N0YIIye2GjU= =SPJu -----END PGP SIGNATURE----- --/9DWx/yDrRhgMJTb--