Re: usb-storage data transfer anomaly

[Matthew Dharm <mdharm-usb@one-eyed-alien.net>]

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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
> 
> 
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-- 
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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