usb-storage data transfer anomaly

usb-storage data transfer anomaly

[Bajo, Allison]

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

Re: usb-storage data transfer anomaly

[Matthew Dharm]

[-- Attachment #1: Type: text/plain, Size: 1795 bytes --]

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

[-- Attachment #2: Type: application/pgp-signature, Size: 232 bytes --]