Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758052AbXJaMUb (ORCPT ); Wed, 31 Oct 2007 08:20:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755850AbXJaMUU (ORCPT ); Wed, 31 Oct 2007 08:20:20 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:54386 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755235AbXJaMUS (ORCPT ); Wed, 31 Oct 2007 08:20:18 -0400 Message-ID: <472872F6.70802@garzik.org> Date: Wed, 31 Oct 2007 08:20:06 -0400 From: Jeff Garzik User-Agent: Thunderbird 2.0.0.5 (X11/20070727) MIME-Version: 1.0 To: Jens Axboe CC: Alan Cox , Daniel Drake , linux list , linux-ide@vger.kernel.org Subject: Re: "Fix ATAPI transfer lengths" causes CD writing regression References: <47274A5F.6070409@gentoo.org> <20071030153417.59b9182c@the-village.bc.nu> <47276DCA.1000808@gentoo.org> <20071030190153.373c9347@the-village.bc.nu> <47278439.4030801@gentoo.org> <20071031114958.210bd7cc@the-village.bc.nu> <20071031115754.GK5059@kernel.dk> In-Reply-To: <20071031115754.GK5059@kernel.dk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.1.9 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1461 Lines: 36 Jens Axboe wrote: > On Wed, Oct 31 2007, Alan Cox wrote: >> On Tue, 30 Oct 2007 19:21:29 +0000 >> Daniel Drake wrote: >> >>> Alan Cox wrote: >>>> I would guess Brasero is issuing a command with the length of data >>>> wrongly set. In the old code that might well just produce errors of the >>>> "Umm wtf is this data left over for ?", with the new code the drive is >>>> likely to change state as it knows the transfer size and that will >>>> *correctly* cause an HSM error and what follows. >>>> >>>> Now the question is who gets the length wrong - Brasero or the ata >>>> translation code in libata >>> Brasero does exactly the same as my test app which I attached to my last >>> mail. Is my test app wrong? >> Would need to double check the SCSI specificatons to be sure but I think >> you are asking for less data than the drive wishes to provide. You >> aren't allowed to do that with ATA. > > ide-cd handles this by throwing the excess away, which I think is the > sane way to do this. That's easy for the PIO case. But CD writing is normally DMA, which means you will get a DMA engine exception if the device wants to give you more data than the scatter/gather entries permit. Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/