From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: PATCH: usb-storage-set-last-sector-bug-flag.patch Date: Thu, 24 Jan 2008 09:21:58 -0800 Message-ID: <20080124172158.GC9665@kroah.com> References: <20080120205625.GB28842@kroah.com> <20080123181239.GA21836@kroah.com> <4798C5B4.1000208@s5r6.in-berlin.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <4798C5B4.1000208@s5r6.in-berlin.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-usb-devel-bounces@lists.sourceforge.net Errors-To: linux-usb-devel-bounces@lists.sourceforge.net To: Stefan Richter Cc: USB development list , linux-scsi@vger.kernel.org, USB Storage list , linux-usb@vger.kernel.org, David Brown , James Bottomley , Alan Stern , Hans de Goede , Boaz Harrosh , Matthew Dharm List-Id: linux-scsi@vger.kernel.org On Thu, Jan 24, 2008 at 06:07:00PM +0100, Stefan Richter wrote: > Greg KH wrote: > > I just am worried that we are > > now suddenly keeping access from the last sector for devices that > > currently did work just fine. > > This new workaround doesn't prevent access to the last sector. It only > breaks up a multi-sector access which would also reach the last sector > into several (two? I'm too lazy to look back in the mail thread) > accesses, in order to access the last sector in a dedicated > single-sector access. > > So that's very differently to the fix-capacity workaround. The > fix-capacity workaround manipulates the READ CAPACITY parameter data. > Therefore the fix-capacity workaround is unsafe for non-buggy devices. > > The last-sector-(access-)bug workaround _only_ modifies the command > stream which is sent to the device. A dangerous command is replaced by > equivalent safe commands. These commands are luckily safe for _all_ > devices, buggy and non-buggy ones. The only cost of this workaround is > (1.) the code, (2.) the runtime/ bandwidth/ latency overhead for > accesses which reach the last sector. Ok, thanks for explaining it better. I have no objection to this change anymore. thanks, greg k-h ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel