From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1944DC433DF for ; Wed, 29 Jul 2020 14:32:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04161207E8 for ; Wed, 29 Jul 2020 14:32:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726772AbgG2OcO (ORCPT ); Wed, 29 Jul 2020 10:32:14 -0400 Received: from netrider.rowland.org ([192.131.102.5]:47953 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1726449AbgG2OcO (ORCPT ); Wed, 29 Jul 2020 10:32:14 -0400 Received: (qmail 1533731 invoked by uid 1000); 29 Jul 2020 10:32:13 -0400 Date: Wed, 29 Jul 2020 10:32:13 -0400 From: Alan Stern To: Martin Kepplinger Cc: Bart Van Assche , jejb@linux.ibm.com, Can Guo , martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@puri.sm Subject: Re: [PATCH] scsi: sd: add runtime pm to open / release Message-ID: <20200729143213.GC1530967@rowland.harvard.edu> References: <20200706164135.GE704149@rowland.harvard.edu> <20200728200243.GA1511887@rowland.harvard.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Wed, Jul 29, 2020 at 04:12:22PM +0200, Martin Kepplinger wrote: > On 28.07.20 22:02, Alan Stern wrote: > > On Tue, Jul 28, 2020 at 09:02:44AM +0200, Martin Kepplinger wrote: > >> Hi Alan, > >> > >> Any API cleanup is of course welcome. I just wanted to remind you that > >> the underlying problem: broken block device runtime pm. Your initial > >> proposed fix "almost" did it and mounting works but during file access, > >> it still just looks like a runtime_resume is missing somewhere. > > > > Well, I have tested that proposed fix several times, and on my system > > it's working perfectly. When I stop accessing a drive it autosuspends, > > and when I access it again it gets resumed and works -- as you would > > expect. > > that's weird. when I mount, everything looks good, "sda1". But as soon > as I cd to the mountpoint and do "ls" (on another SD card "ls" works but > actual file reading leads to the exact same errors), I get: > > [ 77.474632] sd 0:0:0:0: [sda] tag#0 UNKNOWN(0x2003) Result: > hostbyte=0x00 driverbyte=0x08 cmd_age=0s > [ 77.474647] sd 0:0:0:0: [sda] tag#0 Sense Key : 0x6 [current] > [ 77.474655] sd 0:0:0:0: [sda] tag#0 ASC=0x28 ASCQ=0x0 > [ 77.474667] sd 0:0:0:0: [sda] tag#0 CDB: opcode=0x28 28 00 00 00 60 > 40 00 00 01 00 This error report comes from the SCSI layer, not the block layer. > [ 77.474678] blk_update_request: I/O error, dev sda, sector 24640 op > 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 > [ 77.485836] sd 0:0:0:0: [sda] tag#0 device offline or changed > [ 77.491628] blk_update_request: I/O error, dev sda, sector 24641 op > 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 > [ 77.502275] sd 0:0:0:0: [sda] tag#0 device offline or changed > [ 77.508051] blk_update_request: I/O error, dev sda, sector 24642 op > 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 > [ 77.518651] sd 0:0:0:0: [sda] tag#0 device offline or changed > (...) > [ 77.947653] sd 0:0:0:0: [sda] tag#0 device offline or changed > [ 77.953434] FAT-fs (sda1): Directory bread(block 16448) failed > [ 77.959333] sd 0:0:0:0: [sda] tag#0 device offline or changed > [ 77.965118] FAT-fs (sda1): Directory bread(block 16449) failed > [ 77.971014] sd 0:0:0:0: [sda] tag#0 device offline or changed > [ 77.976802] FAT-fs (sda1): Directory bread(block 16450) failed > [ 77.982698] sd 0:0:0:0: [sda] tag#0 device offline or changed > (...) > [ 78.384929] FAT-fs (sda1): Filesystem has been set read-only > [ 103.070973] sd 0:0:0:0: [sda] tag#0 device offline or changed > [ 103.076751] print_req_error: 118 callbacks suppressed > [ 103.076760] blk_update_request: I/O error, dev sda, sector 9748 op > 0x1:(WRITE) flags 0x100000 phys_seg 1 prio class 0 > [ 103.087428] Buffer I/O error on dev sda1, logical block 1556, lost > async page write > [ 103.095309] sd 0:0:0:0: [sda] tag#0 device offline or changed > [ 103.101123] blk_update_request: I/O error, dev sda, sector 17162 op > 0x1:(WRITE) flags 0x100000 phys_seg 1 prio class 0 > [ 103.111883] Buffer I/O error on dev sda1, logical block 8970, lost > async page write I can't tell why you're getting that error. In one of my tests the device returned the same kind of error status (Sense Key = 6, ASC = 0x28) but the operation was then retried successfully. Perhaps the problem lies in the device you are testing. > >> As we need to have that working at some point, I might look into it, but > >> someone who has experience in the block layer can surely do it more > >> efficiently. > > > > I suspect that any problems you still face are caused by something else. > > > > I then formatted sda1 to ext2 (on the runtime suspend system testing > your patch) and that seems to have worked! > > Again accessing the mountpoint then yield the very same "device offline > or changed" errors. > > What kind of device are you testing? You should be easily able to > reproduce this using an "sd" device. I tested two devices: a SanDisk Cruzer USB flash drive and a g-mass-storage gadget running under dummy-hcd. They each showed up as /dev/sdb on my system. I haven't tried testing with an SD card. If you have any specific sequence of commands you would like me to run, let me know. > The problems must lie in the different other drivers we use I guess. Or the devices. Have you tried testing with a USB flash drive? Alan Stern