From: Martin Kepplinger <martin.kepplinger@puri.sm> To: Alan Stern <stern@rowland.harvard.edu> Cc: James Bottomley <James.Bottomley@hansenpartnership.com>, Bart Van Assche <bvanassche@acm.org>, Can Guo <cang@codeaurora.org>, 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 Date: Fri, 7 Aug 2020 11:51:21 +0200 Message-ID: <425990b3-4b0b-4dcf-24dc-4e7e60d5869d@puri.sm> (raw) In-Reply-To: <9b80ca7c-39f8-e52d-2535-8b0baf93c7d1@puri.sm> On 04.08.20 11:39, Martin Kepplinger wrote: > On 30.07.20 17:10, Alan Stern wrote: >> On Thu, Jul 30, 2020 at 10:52:14AM +0200, Martin Kepplinger wrote: >>> Maybe I should just start a new discussion with a patch, but the below >>> is what makes sense to me (when I understand you correctly) and seems to >>> work. I basically add a new flag, so that the old flags behave unchanged >>> and only call it during *runtime* resume for SD cards: >>> >>> >>> --- a/drivers/scsi/scsi_error.c >>> +++ b/drivers/scsi/scsi_error.c >>> @@ -553,15 +553,21 @@ int scsi_check_sense(struct scsi_cmnd *scmd) >>> * information that we should pass up to the upper-level >>> driver >>> * so that we can deal with it there. >>> */ >>> - if (scmd->device->expecting_cc_ua) { >>> + if (scmd->device->expecting_cc_ua || >>> + scmd->device->expecting_media_change) { >>> /* >>> * Because some device does not queue unit >>> * attentions correctly, we carefully check >>> * additional sense code and qualifier so as >>> - * not to squash media change unit attention. >>> + * not to squash media change unit attention; >>> + * unless expecting_media_change is set, indicating >>> + * that the media (most likely) didn't change >>> + * but a device only believes so (for example >>> + * because of suspend/resume). >>> */ >>> - if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) { >>> - scmd->device->expecting_cc_ua = 0; >>> + if ((sshdr.asc != 0x28 || sshdr.ascq != 0x00) || >>> + scmd->device->expecting_media_change) { >>> + scmd->device->expecting_media_change = 0; >>> return NEEDS_RETRY; >>> } >>> } >>> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c >>> index d90fefffe31b..b647fab2b663 100644 >>> --- a/drivers/scsi/sd.c >>> +++ b/drivers/scsi/sd.c >>> @@ -114,6 +114,7 @@ static void sd_shutdown(struct device *); >>> static int sd_suspend_system(struct device *); >>> static int sd_suspend_runtime(struct device *); >>> static int sd_resume(struct device *); >>> +static int sd_resume_runtime(struct device *); >>> static void sd_rescan(struct device *); >>> static blk_status_t sd_init_command(struct scsi_cmnd *SCpnt); >>> static void sd_uninit_command(struct scsi_cmnd *SCpnt); >>> @@ -574,7 +575,7 @@ static const struct dev_pm_ops sd_pm_ops = { >>> .poweroff = sd_suspend_system, >>> .restore = sd_resume, >>> .runtime_suspend = sd_suspend_runtime, >>> - .runtime_resume = sd_resume, >>> + .runtime_resume = sd_resume_runtime, >>> }; >>> >>> static struct scsi_driver sd_template = { >>> @@ -3652,6 +3653,21 @@ static int sd_resume(struct device *dev) >>> return ret; >>> } >>> >>> +static int sd_resume_runtime(struct device *dev) >>> +{ >>> + struct scsi_disk *sdkp = dev_get_drvdata(dev); >>> + >>> + /* Some SD cardreaders report media change when resuming from >>> suspend >>> + * because they can't keep track during suspend. */ >>> + >>> + /* XXX This is not unproblematic though: We won't notice when a card >>> + * was really changed during runtime suspend! We basically rely >>> on users >>> + * to unmount or suspend before doing so. */ >>> + sdkp->device->expecting_media_change = 1; >>> + >>> + return sd_resume(dev); >>> +} >>> + >>> /** >>> * init_sd - entry point for this driver (both when built in or when >>> * a module). >>> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h >>> index bc5909033d13..8c8f053f71c8 100644 >>> --- a/include/scsi/scsi_device.h >>> +++ b/include/scsi/scsi_device.h >>> @@ -169,6 +169,8 @@ struct scsi_device { >>> * this device */ >>> unsigned expecting_cc_ua:1; /* Expecting a CHECK_CONDITION/UNIT_ATTN >>> * because we did a bus reset. */ >>> + unsigned expecting_media_change:1; /* Expecting media change >>> ASC/ASCQ >>> + when it actually doesn't >>> change */ >>> unsigned use_10_for_rw:1; /* first try 10-byte read / write */ >>> unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */ >>> unsigned set_dbd_for_ms:1; /* Set "DBD" field in mode sense */ >> >> That's pretty much what James was suggesting, except for one thing: You >> must not set sdkp->device->expecting_media_change to 1 for all devices >> in sd_runtime_resume(). Only for devices which may generate a spurious >> Unit Attention following runtime resume -- and maybe not even for all of >> them, depending on what the user wants. >> >> Alan Stern >> > > when I mount the SD card myself or via Nautilus, things work. When I put > sth like: > > /dev/sda1 /mnt/sda1 auto auto,nofail 0 2 > > into fstab, I *still* get (constantly) when accessing the files: > > [ 50.838061] sd 0:0:0:0: [sda] tag#0 device offline or changed > > why could that be? is there another place we would add such a new flag > (not only resume())? > > martin > it's really strange: below is the change I'm trying. Of course that's only for testing the functionality, nothing how a patch could look like. While I remember it had worked, now (weirdly since I tried that mounting via fstab) it doesn't anymore! What I understand (not much): I handle the error with "retry" via the new flag, but scsi_decide_disposition() returns SUCCESS because of "no more retries"; but it's the first and only time it's called. How can this be? What am I missing? --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -565,6 +565,13 @@ int scsi_check_sense(struct scsi_cmnd *scmd) return NEEDS_RETRY; } } + if (scmd->device->expecting_media_change) { + if (sshdr.asc == 0x28 && sshdr.ascq == 0x00) { + scmd->device->expecting_media_change = 0; + return NEEDS_RETRY; + } + } + /* * we might also expect a cc/ua if another LUN on the target * reported a UA with an ASC/ASCQ of 3F 0E - diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index d90fefffe31b..bb583e403b81 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3642,6 +3642,8 @@ static int sd_resume(struct device *dev) if (!sdkp) /* E.g.: runtime resume at the start of sd_probe() */ return 0; + sdkp->device->expecting_media_change = 1; + if (!sdkp->device->manage_start_stop) return 0; diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index bc5909033d13..f5fc1af68e00 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -169,6 +169,7 @@ struct scsi_device { * this device */ unsigned expecting_cc_ua:1; /* Expecting a CHECK_CONDITION/UNIT_ATTN * because we did a bus reset. */ + unsigned expecting_media_change:1; unsigned use_10_for_rw:1; /* first try 10-byte read / write */ unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */ unsigned set_dbd_for_ms:1; /* Set "DBD" field in mode sense */
next prev parent reply index Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-23 11:10 Martin Kepplinger 2020-06-24 13:33 ` Bart Van Assche 2020-06-25 8:16 ` Martin Kepplinger 2020-06-25 14:52 ` Alan Stern 2020-06-26 3:53 ` Bart Van Assche 2020-06-26 15:07 ` Bart Van Assche 2020-06-26 15:44 ` Alan Stern 2020-06-28 2:37 ` Bart Van Assche 2020-06-28 13:10 ` Alan Stern 2020-06-29 9:42 ` Martin Kepplinger 2020-06-29 16:15 ` Alan Stern 2020-06-29 16:56 ` Bart Van Assche 2020-06-29 17:40 ` Alan Stern 2020-06-30 3:33 ` Martin Kepplinger 2020-06-30 13:38 ` Alan Stern 2020-06-30 15:59 ` Bart Van Assche 2020-06-30 18:02 ` Alan Stern 2020-06-30 19:23 ` Bart Van Assche 2020-06-30 19:38 ` Alan Stern 2020-06-30 23:31 ` Bart Van Assche 2020-07-01 0:49 ` Alan Stern 2020-07-06 16:41 ` Alan Stern 2020-07-28 7:02 ` Martin Kepplinger 2020-07-28 20:02 ` Alan Stern 2020-07-29 14:12 ` Martin Kepplinger 2020-07-29 14:32 ` Alan Stern 2020-07-29 14:44 ` Martin K. Petersen 2020-07-29 14:56 ` Alan Stern 2020-07-29 14:46 ` James Bottomley 2020-07-29 14:53 ` James Bottomley 2020-07-29 15:40 ` Martin Kepplinger 2020-07-29 15:44 ` James Bottomley 2020-07-29 16:43 ` Martin Kepplinger 2020-07-29 18:25 ` Alan Stern 2020-07-29 18:29 ` James Bottomley 2020-07-30 8:52 ` Martin Kepplinger 2020-07-30 8:54 ` Martin Kepplinger 2020-07-30 15:10 ` Alan Stern 2020-08-04 9:39 ` Martin Kepplinger 2020-08-07 9:51 ` Martin Kepplinger [this message] 2020-08-07 14:30 ` Alan Stern 2020-08-08 6:59 ` Martin Kepplinger 2020-08-08 15:05 ` Alan Stern 2020-08-09 9:20 ` Martin Kepplinger 2020-08-09 15:26 ` Alan Stern 2020-08-10 12:03 ` Martin Kepplinger 2020-08-10 14:13 ` Alan Stern 2020-08-11 7:55 ` Martin Kepplinger 2020-08-11 13:48 ` Alan Stern 2020-08-23 14:57 ` [PATCH] block: Fix bug in runtime-resume handling Alan Stern 2020-08-24 17:48 ` Bart Van Assche 2020-08-24 20:13 ` Alan Stern 2020-08-26 7:48 ` Martin Kepplinger 2020-08-27 17:42 ` Martin Kepplinger 2020-08-27 20:29 ` Alan Stern 2020-08-29 7:24 ` Martin Kepplinger 2020-08-29 15:26 ` Alan Stern 2020-08-29 16:33 ` Martin Kepplinger 2020-08-29 18:56 ` Alan Stern 2020-08-30 0:38 ` Bart Van Assche 2020-08-30 1:06 ` Alan Stern 2020-07-29 15:40 ` [PATCH] scsi: sd: add runtime pm to open / release Alan Stern 2020-07-29 15:49 ` James Bottomley 2020-07-29 16:17 ` Alan Stern 2020-07-29 15:52 ` Martin Kepplinger 2020-07-29 18:10 ` Douglas Gilbert 2020-07-30 8:05 ` Martin Kepplinger 2020-07-30 15:14 ` Alan Stern
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