From: Tomas Styblo <tripie@cpan.org>
To: Robert Hancock <hancockr@shaw.ca>
Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
usb-storage@lists.one-eyed-alien.net
Subject: Re: [PATCH] JMicron JM20337 USB-SATA data corruption bugfix - device 152d:2338
Date: Tue, 22 Jul 2008 07:11:10 +0200 [thread overview]
Message-ID: <20080722051110.GA8303@notebook.homenet.local> (raw)
In-Reply-To: <4884E585.2050104@shaw.ca>
* Robert Hancock <hancockr@shaw.ca> [Mon, 21 Jul 2008]:
>
> I'm not sure this is a good approach. More that this code right above in
> usb_stor_invoke_transport, which your code undoes the effect of for this
> device, doesn't seem right:
>
> /* If things are really okay, then let's show that. Zero
> * out the sense buffer so the higher layers won't realize
> * we did an unsolicited auto-sense. */
> if (result == USB_STOR_TRANSPORT_GOOD &&
> /* Filemark 0, ignore EOM, ILI 0, no sense */
> (srb->sense_buffer[2] & 0xaf) == 0 &&
> /* No ASC or ASCQ */
> srb->sense_buffer[12] == 0 &&
> srb->sense_buffer[13] == 0) {
> srb->result = SAM_STAT_GOOD;
> srb->sense_buffer[0] = 0x0;
> }
>
The patch doesn't exactly undo the effect of the code above,
because the value of _result_ is different. When this problem
happens, the condition above is false, _result_ is
USB_STOR_TRANSPORT_FAILED and scsi_get_resid(srb) > 0, but the
chipset doesn't report any error (NO_SENSE,ASC==0,ASCQ==0). That's
why I think there's something wrong with the chipset.
There are Windows users on various message boards who report the
same problem with this chipset - a kind of silent data corruption
that occurs only when copying large amounts of data.
But as I said I know little about SCSI and USB. I tried to locate
and fix the problem, but I can't tell whether the current error
handling code is written according to the relevant standards.
A more generic approach would certainly be better than hardcoded
device ids. Perhaps this check should be enabled for all devices?
Why not?
--
Tomas Styblo <tripie@cpan.org>
next prev parent reply other threads:[~2008-07-22 5:11 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <fa.eWQqoO1e4Mdhu8SK5jzMFAI/3NU@ifi.uio.no>
2008-07-21 19:37 ` [PATCH] JMicron JM20337 USB-SATA data corruption bugfix - device 152d:2338 Robert Hancock
2008-07-22 2:37 ` Alan Stern
2008-07-22 9:03 ` Tomas Styblo
2008-07-23 2:38 ` Alan Stern
2008-07-23 23:20 ` Robert Hancock
2008-07-24 3:42 ` Alan Stern
2008-07-30 19:55 ` Robert Hancock
2008-07-30 20:00 ` [usb-storage] " Matthew Dharm
2008-07-30 20:46 ` Robert Hancock
2008-07-30 21:18 ` Alan Stern
2008-07-30 21:07 ` Alan Stern
2008-08-01 21:15 ` Alex Buell
2008-08-01 22:22 ` Alex Buell
2008-08-02 2:32 ` Robert Hancock
2008-08-02 23:49 ` Alan Stern
2008-08-03 9:07 ` Alex Buell
2008-08-04 16:48 ` Alan Stern
2008-08-04 20:17 ` Alex Buell
2008-08-04 20:45 ` Alan Stern
2008-09-02 12:10 ` Thiago Galesi
2008-09-02 15:02 ` Alan Stern
2008-09-02 16:07 ` Thiago Galesi
2008-09-02 19:19 ` Alan Stern
2008-09-02 20:16 ` Thiago Galesi
2008-09-02 21:06 ` Alan Stern
2008-09-04 12:09 ` Thiago Galesi
2008-09-04 14:03 ` Alan Stern
2008-09-04 15:17 ` Thiago Galesi
2008-09-04 15:26 ` Alan Stern
2008-07-25 8:44 ` Tomas Styblo
2008-07-25 8:54 ` Robert Hancock
2008-07-22 5:11 ` Tomas Styblo [this message]
2008-07-22 5:31 ` Robert Hancock
2008-07-22 6:11 ` Tomas Styblo
2008-07-22 8:45 ` Robert Hancock
2008-07-24 6:15 ` Alex Buell
2008-07-29 21:09 ` Alex Buell
2008-07-29 22:33 ` [usb-storage] " Matthew Dharm
2008-07-20 5:13 Tomas Styblo
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