From: Martin Kepplinger <martin.kepplinger@puri.sm>
To: James Bottomley <James.Bottomley@HansenPartnership.com>,
Alan Stern <stern@rowland.harvard.edu>
Cc: 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: Wed, 29 Jul 2020 18:43:48 +0200 [thread overview]
Message-ID: <A1653792-B7E5-46A9-835B-7FA85FCD0378@puri.sm> (raw)
In-Reply-To: <1596037482.4356.37.camel@HansenPartnership.com>
Am 29. Juli 2020 17:44:42 MESZ schrieb James Bottomley <James.Bottomley@HansenPartnership.com>:
>On Wed, 2020-07-29 at 17:40 +0200, Martin Kepplinger wrote:
>> On 29.07.20 16:53, James Bottomley wrote:
>> > On Wed, 2020-07-29 at 07:46 -0700, James Bottomley wrote:
>> > > On Wed, 2020-07-29 at 10:32 -0400, Alan Stern wrote:
>[...]
>> > > > This error report comes from the SCSI layer, not the block
>> > > > layer.
>> > >
>> > > That sense code means "NOT READY TO READY CHANGE, MEDIUM MAY HAVE
>> > > CHANGED" so it sounds like it something we should be
>> > > ignoring. Usually this signals a problem, like you changed the
>> > > medium manually (ejected the CD). But in this case you can tell
>> > > us to expect this by setting
>> > >
>> > > sdev->expecting_cc_ua
>> > >
>> > > And we'll retry. I think you need to set this on all resumed
>> > > devices.
>> >
>> > Actually, it's not quite that easy, we filter out this ASC/ASCQ
>> > combination from the check because we should never ignore medium
>> > might have changed events on running devices. We could ignore it
>> > if we had a flag to say the power has been yanked (perhaps an
>> > additional sdev flag you set on resume) but we would still miss the
>> > case where you really had powered off the drive and then changed
>> > the media ... if you can regard this as the user's problem, then we
>> > might have a solution.
>> >
>> > James
>> >
>>
>> oh I see what you mean now, thanks for the ellaboration.
>>
>> if I do the following change, things all look normal and runtime pm
>> works. I'm not 100% sure if just setting expecting_cc_ua in resume()
>> is "correct" but that looks like it is what you're talking about:
>>
>> (note that this is of course with the one block layer diff applied
>> that Alan posted a few emails back)
>>
>>
>> --- a/drivers/scsi/scsi_error.c
>> +++ b/drivers/scsi/scsi_error.c
>> @@ -554,16 +554,8 @@ int scsi_check_sense(struct scsi_cmnd *scmd)
>> * so that we can deal with it there.
>> */
>> if (scmd->device->expecting_cc_ua) {
>> - /*
>> - * 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.
>> - */
>> - if (sshdr.asc != 0x28 || sshdr.ascq != 0x00)
>> {
>> - scmd->device->expecting_cc_ua = 0;
>> - return NEEDS_RETRY;
>> - }
>> + scmd->device->expecting_cc_ua = 0;
>> + return NEEDS_RETRY;
>
>Well, yes, but you can't do this because it would lose us media change
>events in the non-suspend/resume case which we really don't want.
>That's why I was suggesting a new flag.
>
>James
also if I set expecting_cc_ua in resume() only, like I did?
--
Martin Kepplinger
xmpp: martink@jabber.at
Sent from mobile.
next prev parent reply other threads:[~2020-07-29 16:44 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 11:10 [PATCH] scsi: sd: add runtime pm to open / release 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 [this message]
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
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
2020-07-29 15:40 ` 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=A1653792-B7E5-46A9-835B-7FA85FCD0378@puri.sm \
--to=martin.kepplinger@puri.sm \
--cc=James.Bottomley@HansenPartnership.com \
--cc=bvanassche@acm.org \
--cc=cang@codeaurora.org \
--cc=kernel@puri.sm \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=stern@rowland.harvard.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).