From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Warner Subject: Re: libata oops 2.6.11-rc4 yesterdays BK Date: Thu, 17 Feb 2005 13:25:00 -0600 Message-ID: <20050217132500.N10699@florence.linkmargin.com> References: <4213821D.1030203@pobox.com> <4213B2F8.2070800@wasp.net.au> <20050216154033.I10699@florence.linkmargin.com> <4213CD9E.9040703@pobox.com> <20050216174954.K10699@florence.linkmargin.com> <4213DE38.70309@pobox.com> <20050216182040.L10699@florence.linkmargin.com> <421426DB.2000308@pobox.com> <20050217085934.M10699@florence.linkmargin.com> <4214ECE9.7070502@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Received: from ms-smtp-01.rdc-kc.rr.com ([24.94.166.115]:25742 "EHLO ms-smtp-01.rdc-kc.rr.com") by vger.kernel.org with ESMTP id S262370AbVBQTZI (ORCPT ); Thu, 17 Feb 2005 14:25:08 -0500 Content-Disposition: inline In-Reply-To: <4214ECE9.7070502@pobox.com>; from jgarzik@pobox.com on Thu, Feb 17, 2005 at 02:13:45PM -0500 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: Andy Warner , Bartlomiej Zolnierkiewicz , linux-ide@vger.kernel.org Jeff Garzik wrote: > [...] > AHCI is the first scenario where PIO-via-DMA could be utilized in an > efficient manner. The upcoming SiI 3124 is another. A few others > (ADMA, Marvell) are PIO-via-DMA controllers as well. I agree this is a > good thing. I _think_ the SATA-II stuff from Promise (20579) does this too. > Anyway, getting back to the thread of "problems with PIO polling", I am > wondering if -- due to SATA's nature -- PIO polling should be avoided, > and interrupt-driven methodology used instead. > > One reason why PIO polling was chosen (for controllers that support it; > AHCI does not) is that the entire command submission/processing code can > be written inline: just submit-command, wait-for-busy-clear, etc. > Makes the code less complex. I think going interrupt driven would be a good idea. Of course when I tried it one chip didn't serve up the interrupt as expected (can't remember is it was the 3114 or the 20319 - would have to check my notes.) I don't think it is massively more complex than what we currently have, and quite possibly might be simpler. -- andyw@pobox.com Andy Warner Voice: (612) 801-8549 Fax: (208) 575-5634