From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rwcrmhc14.comcast.net (rwcrmhc14.comcast.net [204.127.192.84]) by ozlabs.org (Postfix) with ESMTP id BEF2E67CED for ; Wed, 8 Nov 2006 17:23:03 +1100 (EST) Message-ID: <4551768F.9040601@heckheck.com> Date: Wed, 08 Nov 2006 01:17:51 -0500 From: Jim Heck MIME-Version: 1.0 To: robin.gilks@tait.co.nz Subject: Re: 2.6.18 fails in call_usermodedata() on 8xx References: <45512174.7020205@tait.co.nz> In-Reply-To: <45512174.7020205@tait.co.nz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: ppc embedded list List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Robin, Could you provide some more details of your problem with dma_alloc_init for the 8xx. I posted a few days back on Saturday about problems I was having getting an RPXLiteDW (based on the 823) to work with a late 2.6.xx kernel. I had traced the problem down (working without a probe) to problems with cpm_dpalloc() and cpm_dpram_addr() in the allocation of DP Ram buffers for the network loopback device. DMA rings a bell since the failure occurred near where the /arch/ppc/8xx_io/enet.c driver is calling dma_alloc_coherent(). The details on what code you had to change in the kernel, and the problems you were seeing might help me greatly. Thanks for any help, -Jim Heck Robin Gilks wrote: > Greetings > > Having (sort of) mastered the bdi2000, I'm trying to bring up a 8xx card > thats been debugged and working with a 2.4 kernel for the last 3 years > but is failing miserably on a 2.6.18 kernel. > > My initial problems in dma_alloc_init I seem to have fixed by moving > CONFIG_CONSISTENT_START to 0xa0000000 from the default of 0xff100000 but > now I'm failing in call_usermodedata(). Any attempt to check the values > of structures (eg. current->fs->root) results in an error of the form: > > (gdb) print *current > Cannot access memory at address 0xc01e27a8 > > so I'm a bit stuck with further debugging. > > Is there anything I should be looking out for in particular with an 8xx > CPU and a late 2.6 kernel? My understanding was that it now worked but > the config documentation is a bit thin on the ground :-( > > Cheers > >