Re: Unit attention in USB storage

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

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I suggest trying this with 2.4.5 -- several people report that kernel works
much better than previous ones with usb-storage.

While the debugging print might be useful... I think another approach might
be in order.  Can you send the data from /proc/bus/usb/devices for
analysis?

Matt

On Tue, Jun 05, 2001 at 03:58:03AM +0200, Andries.Brouwer@cwi.nl wrote:
> Last month my CF reader read CF cards happily.
> Now that I returned from Denmark, I find that it no longer works
> (with the same 2.4.3 kernel). Indeed, it is not properly detected.
> 
> The reason seems to be slightly different timing at bootup -
> maybe because I connected a wheelmouse this time -
> and now this device comes with Unit Attention
> 	(code 70, key 6, ASC 28, ASCQ 0: not ready to ready transit)
> and this is regarded as an error return and the initial INQUIRY fails.
> 
> Thus, since this code actually occurs in real life, we should
> probably add
> 
> 	case 0x2800: what="not ready to ready transtion (media change?)";
> 		break;
> 
> in debug.c:usb_stor_show_sense().
> I have not really thought about the proper treatment of this Unit Attention.
> However, if one decides that really nothing at all is wrong when a device
> tells us that it is ready now, then
> 
>                 if ((srb->sense_buffer[2] & 0xf) == 0x6 /* unit attention */
>                     && srb->sense_buffer[12] == 0x28
>                     && srb->sense_buffer[13] == 0 /* not ready -> ready */)
>                         srb->result = GOOD << 1;
> 
> is perhaps not too unreasonable. (This is in usb/storage/transport.c,
> usb_stor_invoke_transport(), at the end of the need autosense part.)
> Anyway, with this addition (to 2.4.3) all works for me again.
> 
> Andries

-- 
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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