From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933626AbYDNSYI (ORCPT ); Mon, 14 Apr 2008 14:24:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933321AbYDNSV4 (ORCPT ); Mon, 14 Apr 2008 14:21:56 -0400 Received: from mailgw1.fraunhofer.de ([153.96.1.17]:21832 "EHLO mailgw1.fraunhofer.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933313AbYDNSVy (ORCPT ); Mon, 14 Apr 2008 14:21:54 -0400 Date: Mon, 14 Apr 2008 20:21:30 +0200 From: Joerg.Schilling@fokus.fraunhofer.de (Joerg Schilling) To: alan@lxorguk.ukuu.org.uk Cc: linux-kernel@vger.kernel.org, htejun@gmail.com Subject: Re: Again... DMA speed too slow Message-ID: <4803a0aa.MFfq4lGLYeJxd4mH%Joerg.Schilling@fokus.fraunhofer.de> References: <48038c3e.P3RWjRNXsDrhjIX7%Joerg.Schilling@fokus.fraunhofer.de> <20080414175636.4ea815dc@core> <48039208.H1ySWf8m1sXKYjHZ%Joerg.Schilling@fokus.fraunhofer.de> <20080414182918.4779b8ea@core> In-Reply-To: <20080414182918.4779b8ea@core> User-Agent: nail 11.22 3/20/05 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-OriginalArrivalTime: 14 Apr 2008 18:21:30.0881 (UTC) FILETIME=[5CA8DF10:01C89E5C] X-Fraunhofer-Email-Policy: accepted Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > > OK, I know that a few drives give wrong DMA speed test results on Solaris, > > so the behavior for these drives seems to be unrelated to the OS. > > Controllers don't always get DMA ATAPI right things like that - not > trivial little speed test details. Using the term "controller" is not specific enough to understand what you might like to tell. > > I am not sure why you mention the term "brave", is it because all known Linux > > distributions still require suid root? In this case, I encourage you to inform > > Last time I checked almost all cd burning was being done non root. Looks like you are incorrectly informed in this area or you checked only software that does not work correclty in all cases .... For your information: Linux traditionally needed suid root for sending SCSI commands until someone introduced a bug in late 2.4 kernels. After this bug has been discovered, the Linux Kernel interface has been changed in an incomatible way. At the same time, the Linux kernel started to filter SCSI commands. Some commands that are needed for CD/DVD writing still need root privileges, others don't. Some people did take my working software and removed security checks. The fact that it is possible to still write CDs under some conditions does not prove anything. It justs verifies that the people who removed those checks are not smart enough to find the assignements of the SCSI command codes in cdrecord ;-) Jörg -- EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin js@cs.tu-berlin.de (uni) schilling@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/ URL: http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily