From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: Re: usb hdd problems with 2.6.27.2 Date: Mon, 27 Oct 2008 17:08:54 +0200 Message-ID: <4905D986.6050001@panasas.com> References: <4905D68D.7030407@interlog.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4905D68D.7030407-qazKcTl6WRFWk0Htik3J/w@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: dgilbert-qazKcTl6WRFWk0Htik3J/w@public.gmane.org Cc: Alan Stern , Luciano Rocha , James Bottomley , "Rafael J. Wysocki" , Linux-Kernel , USB list , SCSI development list List-Id: linux-scsi@vger.kernel.org Douglas Gilbert wrote: > > Since the READ CAPACITY "off by one" error is so common, > perhaps drivers such as usb-storage could have a hook to > do a pseudo READ CAPACITY. Then if the capacity value > looked odd (in both senses) the driver could do an IO to > the suspect block and if that failed decrement the capacity > value passed back to the mid level. > Put another way, why don't these defective devices trip up > another OS? > Window$ never reads the last sector unless it is actually written to. I had such a device it got stuck when I wrote to the last sector. > BTW a single disk in RAID 0 (seen on a HP E200 controller) > has a shortened capacity value seen in the midlevel on the > corresponding logical drive. That missing chunk is probably > where the RAID controller puts its control information. > Anyway, playing with the capacity value returned by READ > CAPACITY certainly has a precedent. > >> Later on the system tries to read the contents of what it thinks is the >> last sector: > > I know that happens but it seems strange that upper levels > are reading a block that has never been written to. Read ahead? > That would be udev or hald, I can't remember which. It is a special Linux fixture. ;) > Doug Gilbert > > Boaz -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html