Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757584Ab2EHRDV (ORCPT ); Tue, 8 May 2012 13:03:21 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:38283 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1757552Ab2EHRDS (ORCPT ); Tue, 8 May 2012 13:03:18 -0400 Date: Tue, 8 May 2012 13:03:17 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Paul Bolle cc: "James E.J. Bottomley" , Matthew Dharm , Greg Kroah-Hartman , , , , Subject: Re: [PATCH 0/3] scsi: usb-storage: hide errors for five devices In-Reply-To: <1336491453.1933.67.camel@x61.thuisdomein> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1744 Lines: 46 On Tue, 8 May 2012, Paul Bolle wrote: > On Tue, 2012-05-08 at 10:02 -0400, Alan Stern wrote: > > On Tue, 8 May 2012, Paul Bolle wrote: > > > 1) These patches try to hide those errors by: > > > - downgrading one error to a notice; and > > > > That's a reasonable thing to do, IMO. > > > > > - setting the NO_WP_DETECT quirk for these five devices. > > > > But that isn't. These quirks are intended for devices that crash when > > they receive the command in question. > > Yes, these USB memory sticks don't crash. (They actually seem to work > just fine, something that I perhaps should have emphasized in the commit > descriptions.) > > > They aren't meant to suppress sending commands to devices that can > > properly reject them. > > Even the sticks that hit "bad_sense" (in sd_read_cache_type(), which I > forgot to mention in the comment descriptions)? Is that not as severe as > it suggests? It means that the device either doesn't support the MODE SENSE command or it returned useless data. As a result, we will assume it has a write-through cache when it might not. For memory sticks this doesn't matter. For other devices it might be more important (although anything with a working cache should not hit this error case). > Of course, an easy way out would be to downgrade both the "Asking for > cache data failed" and the "No Caching mode page present" errors to > notices. But the SCSI people might disagree with that approach. Well, let's see what they say. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/