Re: 2.6.24-rc2-mm1

Matthew Dharm
2007-11-14T08:23:55Z

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On Wed, Nov 14, 2007 at 06:33:39AM +0100, Gabriel C wrote:
> Matthew Dharm wrote:
> > On Tue, Nov 13, 2007 at 07:49:24PM -0800, Greg KH wrote:
> >> Matt, are these the errors you were worried about with the patch we were
> >> just talking about tha tis in my tree?
> >
> > I can't tell from these logs.
>
> There is the dmesg with CONFIG_USB_STORAGE_DEBUG :
>
> http://194.231.229.228/dmesg-2.6.24-rc2-mm1

Good news: This isn't the bug Greg was worried about.

Bad news: Something is seriously strange here. Note the following from the
logs:

Nov 14 06:07:43 lara [ 41.890614] usb-storage: Bulk Status S 0x53425355 T 0xd R 0 Stat 0x0
Nov 14 06:07:43 lara [ 41.890616] usb-storage: -- unexpectedly short transfer

Note the 'R' value of zero -- this is the residue value. It indicates a
complete transfer, and that matches the log lines immediately previous
which indicate a 4K transfer which completed properly.

If residue is zero, then srb->resid should be zero. Take a look in
linux/usb/storage/transport.c in usb_stor_Bulk_transport()

If srb->resid is zero, then you should NEVER get the "unexpectedly short
transfer" message. Look at usb_stor_invoke_transport() in the same file.

In fact, every transfer I look at shows this error. I didn't exhaustivly
check every single one in the log, but a quick scan suggests that they all
are bogus; good transfer, CSW residue of 0, and "unexpectedly short"
message.

Maybe I'm too tired at this hour, but I just don't see how this is
possible. Then again, I'm looking at 2.6.22 codebase (it's what I have
handy).

Hrm... does this tree have the "srb accessor" patches in it? I'm wondering
if somewhere the init srb->resid to 0 before invoking the transport got
lost....

Matt

--
Matthew Dharm Home: mdharm-usb@one-eyed-alien.net
Maintainer, Linux USB Mass Storage Driver

Somebody call an exorcist!
-- Dust Puppy
User Friendly, 5/16/1998

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