Date: Tue, 31 Oct 2006 23:08:38 +0100
From: Joerg.Schilling@fokus.fraunhofer.de (Joerg Schilling)
To: schilling@fokus.fraunhofer.de, linux-kernel@vger.kernel.org
Subject: SCSI over USB showstopper bug?
Message-ID: <4547c966.8oyAB/pzCZ7bGUza%Joerg.Schilling@fokus.fraunhofer.de>
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Hi,

it looks as if SG_GET_RESERVED_SIZE & SG_SET_RESERVED_SIZE
are not in interaction with the underlying SCSI transport.

Programs like readcd and cdda2wav that try to get very large SCSI
transfer buffers get a confirmation for nearly any SCSI transfer size 
but later when readcd/cdda2wav try to transfer data with an
actual SCSI command, they fail with ENOMEM.

Correct fix: let sg.c make a callback to the underlying SCSI transport
		and let it get a confirmation tfor the buffer size.

Quick and dirty fix: reduce the maximum allowed DMA size to the smallest
		max DMA size of all SCSI transports.

J?rg

-- 
 EMail:joerg@schily.isdn.cs.tu-berlin.de (home) J?rg Schilling D-13353 Berlin
       js@cs.tu-berlin.de                (uni)  
       schilling@fokus.fraunhofer.de     (work) Blog: http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily
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