From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Tony Battersby" Subject: RE: Sym53c8xx_2 Odd Byte Data Transfer patches Date: Tue, 14 Jun 2005 18:00:38 -0400 Message-ID: <009301c5712c$80200910$e0019d89@cybernetics.com> References: <20050614205041.GB11655@parcelfarce.linux.theplanet.co.uk> Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from cyborg.cybernetics.com ([206.246.200.18]:14601 "EHLO cyborg.cybernetics.com") by vger.kernel.org with ESMTP id S261368AbVFNWCM (ORCPT ); Tue, 14 Jun 2005 18:02:12 -0400 In-Reply-To: <20050614205041.GB11655@parcelfarce.linux.theplanet.co.uk> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: 'Matthew Wilcox' , "'Stephens, Larry'" Cc: "'Linux-Scsi@Vger. Kernel. Org (E-mail)'" > While this patch does seem to solve the problem of transferring an odd > number of bytes to the device, I recently received a bug report saying > that we don't accept an odd number of bytes transferred from a device. > It seems to me that it's going to require modifying the scsi > scripts in > order to do this. Do you agree? Have you looked into > transfers in the > opposite direction as part of this work? If a target sends an odd number of bytes during a wide DATA IN phase, then it should send an IGNORE WIDE RESIDUE message immediately after exiting the data phase to inform the initiator. The sym53c8xx_2 driver in the 2.4 kernel series handles this correctly except on a REQUEST SENSE command issued for autosense (previously sym53c8xx_2 would reject an IWR message for autosense; I submitted a patch a good while ago to make it ignore IWR in this case instead of rejecting it). Not accounting for IWR on autosense is not a big deal though, so I consider sym53c8xx_2 in 2.4 kernels to handle odd-length DATA IN phases acceptably. I haven't tested the 2.6 kernels. Anthony J. Battersby Cybernetics