From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: PATA Sil680 Disabling IRQ Date: Thu, 28 Feb 2008 23:10:02 +0000 Message-ID: <20080228231002.325c9e1d@core> References: <8202f4270802261647t505cccf7ra3c81e5fccc9366a@mail.gmail.com> <47C4B5BE.7010709@garzik.org> <8202f4270802271620u6cea6176p2bea5ff8e0b9bbef@mail.gmail.com> <20080228202255.5e3f0c43@core> <8202f4270802281411j747bf96dx34ff81c4d192d417@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:42047 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1757317AbYB1XUz (ORCPT ); Thu, 28 Feb 2008 18:20:55 -0500 In-Reply-To: <8202f4270802281411j747bf96dx34ff81c4d192d417@mail.gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Fajun Chen Cc: Jeff Garzik , "linux-ide@vger.kernel.org" , Mark Lord , Tejun Heo > For most of unsupported commands, it will be aborted by drive. > However, for some unsupported commands, it may not. I suspect these > bad commands are the new ones in ATA8 issued to some drives with old > firmware. For instance, can you try command 0x5E (Trusted Send PIO > data out) with sector count set to 1 and see what happens? Well the kernel as of 2.6.24 defaults to blocking treacherous computing commands 8) > The blame is probably on drives which should have aborted these > commands. But the reality is that libata will handle variety of drives > including the ones with old firmware. So the question here is whether > libata PATA code can be more fault tolerate. It seems the weakest link > is on PATA PIO since I have not been able to reproduce the IRQ > disabling problem on DMA operations. If you send crap to a drive you will get junk as a result. Only the superuser can do this so that behaviour is fine. The superuser can also crash the machine a million other ways. End users cannot send arbitary commands to the drive. Ditto they may know that an "unsupported" command for their ATA version is actually a vendor private command for the specific drive they have. Alan