Re: PATCH: usb-storage-set-last-sector-bug-flag.patch

[Matthew Dharm <mdharm-scsi@xxxxxxxxxxxxxxxxxx>]

ACKed-by: Matthew Dharm <mdharm-usb@xxxxxxxxxxxxxxxxxx>

Matt

On Fri, Jan 25, 2008 at 11:12:21AM -0600, James Bottomley wrote:
> On Thu, 2008-01-24 at 09:21 -0800, Greg KH wrote:
> > 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.
> 
> So, for forms sake to take this through the SCSI tree I need at least
> one USB person to ack it ...
> 
> James
> 

-- 
Matthew Dharm                              Home: mdharm-usb@xxxxxxxxxxxxxxxxxx 
Maintainer, Linux USB Mass Storage Driver

It was a new hope.
					-- Dust Puppy
User Friendly, 12/25/1998

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