Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755861AbZJKQRV (ORCPT ); Sun, 11 Oct 2009 12:17:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754931AbZJKQRU (ORCPT ); Sun, 11 Oct 2009 12:17:20 -0400 Received: from mail.pc-doctor.com ([66.224.119.10]:59216 "EHLO mail.pc-doctor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753450AbZJKQRT (ORCPT ); Sun, 11 Oct 2009 12:17:19 -0400 Date: Sun, 11 Oct 2009 09:16:38 -0700 (PDT) From: Ben Efros To: Alan Stern Cc: Josua Dietze , fangxiaozhi , Greg KH , Kernel development list , USB list , Hugh Blemings , Benjamin Herrenschmidt Message-ID: <7550119.564321255277798089.JavaMail.root@mail.pc-doctor.com> In-Reply-To: <26767470.564301255277612694.JavaMail.root@mail.pc-doctor.com> Subject: Re: USB serial regression 2.6.31.1 -> 2.6.31.2 [PATCH] MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [99.148.190.25] X-Mailer: Zimbra 5.0.18_GA_3011.UBUNTU6 (ZimbraWebClient - FF3.0 (Linux)/5.0.18_GA_3011.UBUNTU6) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2622 Lines: 66 ----- "Alan Stern" wrote: > On Sun, 11 Oct 2009, Benjamin Herrenschmidt wrote: > > > > > > Further REQUEST SENSE commands therefore requested 96 bytes of > data > > > instead of the standard 18 bytes. With LUN 0 this worked okay. > But > > > with LUN 1 it didn't; the device reported a failure of the REQUEST > > > > SENSE. This is what caused usb-storage to issue the device > reset. > > > > > > After the reset usb-storage continued to ask for 96 bytes of > sense > > > data, and LUN 1 continued to fail the commands. Hence the > repeated > > > resets. > > > > Maybe a better approach would be to go back to 18 bytes when it > fails, > > what do you think ? > > We certainly could do that. But should we turn off the SANE_SENSE > flag > at the same time? No I don't think its a good idea to turn off SANE_SENSE in this situation. Here is a patch similar to Ben Herrenschmidt's but will not turn off SANE_SENSE just because a transport failure. Retry with short sense when SANE_SENSE fails. Signed-off-by: Ben Efros --- linux-2.6.31.1/drivers/usb/storage/transport.c 2009-09-24 08:45:25.000000000 -0700 +++ linux-2.6.31.1.new/drivers/usb/storage/transport.c 2009-10-11 08:06:26.000000000 -0700 @@ -696,7 +696,7 @@ void usb_stor_invoke_transport(struct sc /* device supports and needs bigger sense buffer */ if (us->fflags & US_FL_SANE_SENSE) sense_size = ~0; - +Retry_Sense: US_DEBUGP("Issuing auto-REQUEST_SENSE\n"); scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size); @@ -723,6 +723,12 @@ void usb_stor_invoke_transport(struct sc if (temp_result != USB_STOR_TRANSPORT_GOOD) { US_DEBUGP("-- auto-sense failure\n"); + if ((us->fflags & US_FL_SANE_SENSE) && + sense_size != US_SENSE_SIZE) { + sense_size = US_SENSE_SIZE; + US_DEBUGP("-- retry without SANE_SENSE\n"); + goto Retry_Sense; + } /* we skip the reset if this happens to be a * multi-target device, since failure of an * auto-sense is perfectly valid -- 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/