From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gabriel C Subject: Re: How to Switch DMA off for only one Harddisk at Kernelboot Date: Sun, 16 Dec 2007 20:45:39 +0100 Message-ID: <47658063.5010707@googlemail.com> References: <4765690C.6010605@j-o-a.de> <47657BA8.3020004@googlemail.com> <47657D79.7090100@j-o-a.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <47657D79.7090100@j-o-a.de> Sender: linux-kernel-owner@vger.kernel.org To: Oliver Joa Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org List-Id: linux-ide@vger.kernel.org Oliver Joa wrote: > Hi, > > Gabriel C wrote: >> Oliver Joa wrote: >>> Hi, >> Hi Oliver , >> >>> how can I tell the kernel not to probe DMA for a specific harddisk (e.g. >>> hda). My first Drive (hda) is a Compact-Flash Card which can not do DMA. >>> The kernel tries at boot to switch to DMA but fails. If I use ide=nodma, >>> the kernel boots about 2 minutes faster, but then I can not switch on >>> DMA for the second Drive (hdc) which is a normal Harddisk. Do I have to >>> live with this 2 minutes waiting time or is there another solution? I >>> did not find any kernel-parameter for this purpose. >>> >>> Sorry if I ask here, but I can not find any solution, and I asked >>> already in other groups. >>> >>> Thank you very much >> Should work with hda=nodma or ideX=nodma ( where X is your HDD nr , in your case is 0 ) > > I tried this already, it does not work. > >> Also have a look at Documentation/ide.txt. > > I read this already. Searching for "nodma" in this document gives only > one line: > > "ide=nodma" : disable DMA globally for the IDE subsystem. > > If the documentation is correct hda=nodma and ideX=nodma should not > work. I use kernel 2.6.23.1 at the moment. grep nodma Documentation/ide.txt "hdx=nodma" : disallow DMA ide=foo_option is for the whole ide sub-system where ideX|hdX=foo_option is just for that HDD. Anyway I've CC'ed linux-ide. > > Thanks > > Olli > Gabriel