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From: Cyril Roelandt <tipecaml@gmail.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: USB list <linux-usb@vger.kernel.org>,
	sellis@redhat.com, pachoramos@gmail.com,
	labbott@fedoraproject.org, gregkh@linuxfoundation.org,
	javhera@gmx.com, brice.goglin@gmail.com
Subject: Re: [BUG] Regression in Linux 5.4.17 for JMicron JMS566 enclosure
Date: Sun, 23 Aug 2020 03:30:25 +0200	[thread overview]
Message-ID: <20200823013025.GA11449@Susan> (raw)
In-Reply-To: <20200818145722.GA146472@rowland.harvard.edu>

Hello,

On 2020-08-18 10:57, Alan Stern wrote:
> Somehow that commit is causing usb-storage to go crazy.  You're going
> to have to do some debugging to find out why.
> 
> Here's what to look for in drivers/usb/storage/usb.c:
> 
> 	Is storage_probe() getting called at all?

Yes.

> 
> 	If it is, it doesn't seem to get as far as calling
> 	usb_stor_probe1().  Can you find out where it goes off the
> 	rails and why?

Yes. I added a bunch of calls to printk[1] and noticed the following new
lines in dmesg:

[Fri Aug 21 23:02:42 2020] [+] Entering storage_probe
[Fri Aug 21 23:02:42 2020] [+] Using uas driver

So basically, the kernel realizes that UAS cannot be used, tries to use
usb-storage instead, and then usb-storage says "well, this device should
be using UAS, I'm not going to handle it". Somehow, we forget that UAS
is broken for this device along the way.

I commented out the call to uas_use_uas_driver()[2] and was able to see
my partitions, mount them, read and write data. Everything works as
expected.

Do you have any idea why usb-storage may be led to believe UAS is
suitable for this enclosure?


Cyril


[1] https://framagit.org/Steap/linux/-/commit/f70143e30fb1ca5f3ce7476ce6d51354786c72c9
[2] https://framagit.org/Steap/linux/-/commit/22b3a6ae411bc9fa98d3c81045308ce83f144b14

  reply	other threads:[~2020-08-23  1:30 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-15 20:56 [BUG] Regression in Linux 5.4.17 for JMicron JMS566 enclosure Cyril Roelandt
2020-04-16  1:21 ` Alan Stern
     [not found]   ` <CABLbxQ2Hoq8zt--w2FwuMa6FRCC72E5a-tvGRQOm=C0YF7bfqA@mail.gmail.com>
2020-04-16 14:43     ` Pacho Ramos
2020-04-17 18:32   ` Cyril Roelandt
2020-04-17 20:06     ` Alan Stern
2020-04-17 22:09       ` Cyril Roelandt
2020-04-19 16:03         ` Alan Stern
2020-04-21  3:01           ` Cyril Roelandt
2020-04-21 13:58             ` Alan Stern
2020-08-15  0:18             ` Cyril Roelandt
2020-08-15  2:19               ` Alan Stern
2020-08-15 23:23                 ` Cyril Roelandt
2020-08-16 16:26                   ` Alan Stern
2020-08-18  4:13                     ` Cyril Roelandt
2020-08-18 14:57                       ` Alan Stern
2020-08-23  1:30                         ` Cyril Roelandt [this message]
2020-08-23 14:47                           ` Alan Stern
2020-08-23 18:08                             ` Cyril Roelandt
2020-08-23 22:14                               ` Brice Goglin
2020-08-24  7:40                               ` Greg KH
2020-08-24 17:31                                 ` [PATCH] Ignore UAS for JMicron JMS567 ATA/ATAPI Bridge Cyril Roelandt
2020-08-24 20:18                                   ` Alan Stern
2020-08-25 21:22                                     ` [PATCH v2] " Cyril Roelandt

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