From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH] libata: add support for READ/WRITE LONG Date: Fri, 16 Mar 2007 10:42:28 -0400 Message-ID: <45FAACD4.6000709@rtr.ca> References: <3aac340703102322p362998b9labedc13503702d2b@mail.gmail.com> <45F56800.3040104@rtr.ca> <3aac340703121003l43685599t8dbffe6247879a91@mail.gmail.com> <45F5A523.1080500@rtr.ca> <45FA8D7A.3040504@rtr.ca> <45FAA35C.2090902@ru.mvista.com> <45FAA822.7050208@rtr.ca> <45FAAACE.6000503@ru.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from ottawa-hs-64-26-128-89.s-ip.magma.ca ([64.26.128.89]:1844 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965277AbXCPOma (ORCPT ); Fri, 16 Mar 2007 10:42:30 -0400 In-Reply-To: <45FAAACE.6000503@ru.mvista.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Sergei Shtylyov Cc: Jeff Garzik , Vitaliyi , Tejun Heo , IDE/ATA development list Sergei Shtylyov wrote: > Hello. > > Mark Lord wrote: .. >>> Again, ata_data_xfer() doesn't seem capable of performing ECC >>> read/writes >>> -- the ECC bytes must be transferred in 8-bit mode, AFAIR. >>> ata_data_xfer() >>> can oinly do that for optionally trailing odd byte. > >> I have no idea what that was all about. Care to explain again? > > Care to read the standards? :-/ > >> RWLONG transfer the ECC info 8-bits at a time, using 16-bit words >> to do so, no different from normal. ??? > > From ATA-1: > > "The transfer of the vendor specific bytes shall be one byte at a > time over bits DD0-7 only (8-bits wide)." > Yes, I said that already. 8-bits at a time, but using 16-bit transfers. > Kinda like it says here, in ATA-3 section 7.16: > The transfer of the vendor specifc bytes shall be 16 bit transfers > with the vendor specific byte in bits 7 through 0. Bits 15 through 8 > shall be ignored by the host. But if we really want to be 100% compliant, we could consider dropping to PIO0 for the command. Not worth it, though, as in practice this is not necessary, and it would mess up libata far more than is worthwhile for this effort. Cheers