From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH/RFC] libata: turn on the ATAPI DMADIR support per word 62 (revised) Date: Thu, 20 Apr 2006 18:51:13 -0400 Message-ID: <44481061.30902@garzik.org> References: <44360922.8050801@tw.ibm.com> <44360B05.6050509@garzik.org> <44363D2E.7010700@tw.ibm.com> <4436431C.8070800@tw.ibm.com> <4436A770.70107@garzik.org> <44446C6C.702@tw.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:16031 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S932109AbWDTWvR (ORCPT ); Thu, 20 Apr 2006 18:51:17 -0400 In-Reply-To: <44446C6C.702@tw.ibm.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: albertl@mail.com Cc: linux-ide@vger.kernel.org, Jonathan Benson , Tejun Heo , Carlos Pardo , Doug Maxey , Brian King Albert Lee wrote: > Summary: > SiI 3611 is currently the only known chip that needs DMADIR. > Since SiI 3611 doesn't implement the ATA-7 word 62 or mangle identify > packet device data, it's hard to check the chip and turn on the DMADIR > support automatically. (Currently the libata DMADIR support can be > turned on manually by module parameter.) Wonderful test report, thanks a _bunch_ for investigating this. > To turn on the DMADIR support automatically, maybe we can check whether > the ATAPI device is bridged (by ata_dev_knobble()). If bridged, we can > try to issue a ATAPI DMA read command to check if ATAPI DMA works. > If not work, then try turning on DMADIR or turn off ATAPI DMA. Sounds like more complexity than its worth, for one non-spec-compliant bridge chip. The module option gets the 3611 going, so IMO the current level of support is adequate. BTW, I found a 3611 here, and put it into my primary fileserver, attaching to a DMA-capable PATA CD-RW drive. Jeff