From mboxrd@z Thu Jan  1 00:00:00 1970
From: Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH 1/2] SCSI & usb-storage: add try_rc_10_first flag
Date: Wed, 20 Jun 2012 13:13:10 -0700
Message-ID: <20120620201310.GA8822@kroah.com>
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To: Alan Stern <stern@rowland.harvard.edu>, "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>, Hans de Goede <hdegoede@redhat.com>, Torsten Wohlfarth <towo@siduction.org>, Sturm Flut <sturmflut@lieberbiber.de>, Sergey <sergeyn@gmail.com>, Philippe Valembois - Phil <lephilousophe@users.sourceforge.net>, USB list <linux-usb@vger.kernel.org>, SCSI development list <linux-scsi@vger.kernel.org>

On Wed, Jun 20, 2012 at 04:04:19PM -0400, Alan Stern wrote:
> Several bug reports have been received recently for USB mass-storage
> devices that don't handle READ CAPACITY(16) commands properly.  They
> report bogus sizes, in some cases becoming unusable as a result.
> 
> The bugs were triggered by commit
> 09b6b51b0b6c1b9bb61815baf205e4d74c89ff04 (SCSI & usb-storage: add
> flags for VPD pages and REPORT LUNS), which caused usb-storage to stop
> overriding the SCSI level reported by devices.  By default, the sd
> driver will try READ CAPACITY(16) first for any device whose level is
> above SCSI_SPC_2.
> 
> It seems likely that any device large enough to require the use of
> READ CAPACITY(16) (i.e., 2 TB or more) would be able to handle READ
> CAPACITY(10) commands properly.  Indeed, I don't know of any devices
> that don't handle READ CAPACITY(10) properly.
> 
> Therefore this patch (as1559) adds a new flag telling the sd driver
> to try READ CAPACITY(10) before READ CAPACITY(16), and sets this flag
> for every USB mass-storage device.  If a device really is larger than
> 2 TB, sd will fall back to READ CAPACITY(16) just as it used to.
> 
> This fixes Bugzilla #43391.
> 
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> Acked-by: Hans de Goede <hdegoede@redhat.com>
> CC: "James E.J. Bottomley" <JBottomley@parallels.com>
> CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
> CC: <stable@vger.kernel.org>

James, mind if I take this through my trees?

thanks,

greg k-h