Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756998Ab0DIU2Q (ORCPT ); Fri, 9 Apr 2010 16:28:16 -0400 Received: from rcsinet11.oracle.com ([148.87.113.123]:50084 "EHLO rcsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754713Ab0DIU2O (ORCPT >); Fri, 9 Apr 2010 16:28:14 -0400 Date: Fri, 9 Apr 2010 16:25:33 -0400 From: Konrad Rzeszutek Wilk To: Alan Stern Cc: Pedro Ribeiro , Daniel Mack , Robert Hancock , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Greg KH , alsa-devel@alsa-project.org, linux-usb@vger.kernel.org Subject: Re: [LKML] Re: USB transfer_buffer allocations on 64bit systems Message-ID: <20100409202533.GA8983@phenom.dumpdata.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.19 (2009-01-05) X-Source-IP: acsmt355.oracle.com [141.146.40.155] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090203.4BBF8DA2.0064:SCFMA4539814,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 875 Lines: 22 On Fri, Apr 09, 2010 at 03:34:06PM -0400, Alan Stern wrote: > On Fri, 9 Apr 2010, Pedro Ribeiro wrote: > > > > The DMA pointers do indeed look sane. I wanted to take a deeper look at > > > this and set up a 64bit system today. However, I fail to see the problem > > > here. Pedro, how much RAM does your machine have installed? > > > It has 4 GB. > > That means DMA mapping cannot be the cause of the problem. :-( That isn't entirely true. The BIOS usually allocates a 256 MB ACPI/PCI hole that is under the 4GB. So end up with 3.7 GB, then the 256MB hole, and then right above the 4GB you the the remaining memory: 4.3GB. -- 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/