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From: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
To: linux-hotplug@vger.kernel.org
Subject: Re: usb-storage data transfer anomaly
Date: Thu, 21 Mar 2002 20:49:19 +0000	[thread overview]
Message-ID: <marc-linux-hotplug-101674464600404@msgid-missing> (raw)
In-Reply-To: <marc-linux-hotplug-101670835213830@msgid-missing>

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One idea.... get a different setup.

The device is likely disconnecting because the hub is killing power due to
over-current.  Which is bogus -- I have one of these devices, and I know
their current draw is legit.

Is the hub powered?  Likely that's what you need.

Matt

On Wed, Mar 20, 2002 at 08:53:17PM -0800, Bajo, Allison wrote:
> I was debugging 2.4.19-pre3 using a SanDisk SDDR-31 CF Card Reader when I observed the following behavior:
> 
> 1. The device (SDDR-31) was intermittently disconnected by the hub and then reconnected even though the device was present all the time.  The trigger for this event was plugging in a CF card into the reader.
> 
> 2. As a result of (1), I receive a CSW from a previous CBW before the disconnect and reconnect in (1).
> 
> 3. When usb_stor_Bulk_transport ( ) returns with a USB_STOR_TRANPORT_ERROR, usb_stor_invoke_transport ( ) tries to reset the device but fails on the reset.
> 
> 4.  Any subsequent CBW and CSW pair will be skewed.  The CBW will receive the CSW of a previous CBW.  At this point it is not recoverable except a reboot.
> 
> 
> Example traffic:
> 	CBW 0
> 	CSW 0
> 
> 	Disconnect
> 	Reconnect
> 
> 	CBW 1
> 	CSW 0
> 
> 	CBW 2
> 	CSW 1
> 
> 	...
> 
> I think you get the picture.  Any ideas.
> 
> - Allison B
> 
> 
> _______________________________________________
> Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
> Linux-hotplug-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel

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

I say, what are all those naked people doing?
					-- Big client to Stef
User Friendly, 12/14/1997

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      reply	other threads:[~2002-03-21 20:49 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-03-21  4:53 usb-storage data transfer anomaly Bajo, Allison
2002-03-21 20:49 ` Matthew Dharm [this message]

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