From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: Assorted bugs in the PIIX drivers Date: Mon, 15 May 2006 22:26:39 +0400 Message-ID: <4468C7DF.7090603@ru.mvista.com> References: <1132929808.3298.18.camel@localhost.localdomain> <44689A54.4020307@ru.mvista.com> <1147708783.26686.69.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtsoft2.corbina.net ([85.21.88.2]:6820 "HELO mail.dev.rtsoft.ru") by vger.kernel.org with SMTP id S965132AbWEOS1t (ORCPT ); Mon, 15 May 2006 14:27:49 -0400 In-Reply-To: <1147708783.26686.69.camel@localhost.localdomain> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello. Alan Cox wrote: > On Llu, 2006-05-15 at 19:12 +0400, Sergei Shtylyov wrote: >> For PIO2+ actually, according to Intel's PRM (29860004.pdf), and it's said >> to have no effect in the lower modes. This is actually not very correct since >> when one issues Set Transfer Mode ATA command with the value (8 + PIOn), this >> means select PIO _flow control_ mode n, so -IORDY is assumed to be in use. > PIO2 depends on the drive (there is a drive parameter telling you the > highest timing clock you can do with/without IORDY Yes. But when you're setting any _explicit_ PIO mode with Set Features command, you're tell the drive to use -IORDY at the same time. >>> I'm also not clear if the "no MWDMA0" list has been updated correctly >>> for the newer chipsets. >> What is/was the point for keeping MW DMA 0 support anyway? On PIIX, it's >> greatly slowed down (600 vs 480 ns cycle) and was never "offically" supported >> by Intel. > Some old old drives only do MWDMA0. The Intel docs I have here don't > describe it in any way as "unsupported", They just don't describe it, period. :-) > merely broken on some ICH variants. ICH errata #55: "Note that DMA Mode-0 is an unsupported mode of the ICH." > Alan MBR, Sergei