From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755398AbYBRQts (ORCPT ); Mon, 18 Feb 2008 11:49:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750878AbYBRQtl (ORCPT ); Mon, 18 Feb 2008 11:49:41 -0500 Received: from ik-out-1112.google.com ([66.249.90.180]:45117 "EHLO ik-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750770AbYBRQtk (ORCPT ); Mon, 18 Feb 2008 11:49:40 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:content-type:content-transfer-encoding; b=BCsvEqyPbmrWKxpLtW3VtOO17wRUNA5gwfOpWL3v1TTCg+pdHMGabi/YGnq9HfaoX5sxaiJR8f+pypHOWNhF78ujoq1jLNwOlNVPQBtJvY3px4mwRGWhRttx3QnUMnGYKzBzQsWkc6kNtcx8CnQHw9AyjdWT2EqHYHEHYhdOxHg= Message-ID: <47B9B720.9020000@gmail.com> Date: Mon, 18 Feb 2008 17:49:36 +0100 From: Jiri Slaby User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Ke CC: linux-kernel@vger.kernel.org Subject: Re: PCI DMA address References: <63aa4aaa0802180705i76229711v8ed9fb2b1ea242df@mail.gmail.com> In-Reply-To: <63aa4aaa0802180705i76229711v8ed9fb2b1ea242df@mail.gmail.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/18/2008 04:05 PM, Ke wrote: > Hello all, > How can kernel get the PCI DMA address above 16MB or 64MB? Documentation/DMA* > I hope that the all PCI devices can use a dma address above > 0x1000000 at a higher memory. Depends on how much is the device broken or what it can do. IIRC you'll always get memory from DMA-zone for < ~0U dma_masks on kernels older than 2.6.(around 10). If you set dma_masks to < ~0U, you will probably (in the meaning, kernel will try to allocate from higher space and fall back to the dma-zone) get higher pages nowadays. However I don't know how far this applies also to systems with iommu in retrospective.