From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.chez-thomas.org (hermes.mlbassoc.com [64.234.241.98]) by ozlabs.org (Postfix) with ESMTP id 47149B70D5 for ; Wed, 24 Nov 2010 01:44:17 +1100 (EST) Message-ID: <4CEBD33D.7020603@mlbassoc.com> Date: Tue, 23 Nov 2010 07:44:13 -0700 From: Gary Thomas MIME-Version: 1.0 To: Benjamin Herrenschmidt Subject: Re: Change in PCI behaviour References: <4CE69AF6.6090408@mlbassoc.com> <1290203218.32570.48.camel@pasglop> <4CE95E11.1050606@mlbassoc.com> <4CEA3F87.9080102@mlbassoc.com> <1290457615.32570.67.camel@pasglop> In-Reply-To: <1290457615.32570.67.camel@pasglop> Content-Type: text/plain; charset=UTF-8; format=flowed Cc: Linux PPC Development List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 11/22/2010 01:26 PM, Benjamin Herrenschmidt wrote: > On Mon, 2010-11-22 at 03:01 -0700, Gary Thomas wrote: >> I have a bit more information on this. I'm pretty sure that the failures >> are only happening in my SCSI (SATA actually) code. My board (8347ea) has >> a PCI bus with a SIL SATA controller. This combo works perfectly in 2.6.28. >> In 2.6.32, it will run for a while (possibly quite a while), then timeout >> trying to do a large block write - typically 256 blocks. Once this timeout >> happens, the SIL controller is stuck and accesses to it will eventually >> cause the whole system to hang (as above). >> >> Was there any major change in how PCI or DMA was handled between 2.6.28 >> and 2.6.32? Given the ephemeral nature of these failures (multiple runs >> all eventually fail, but never the same twice), my only hope of fixing it >> will be to have some ideas what might have changed. > > Maybe the changes you did to the PCI outbound windows are now breaking > DMA ? Make sure the outbound and inbound don't overlap for example and > that all RAM is reachable for inbound. Here's what I did to work around this - in my DTS, I set up my PCI as ranges = <0x02000000 0x0 0xC4000000 0xC4000000 0x0 0x1C000000 0x01000000 0x0 0x00000000 0xB8000000 0x0 0x00100000>; Before, I had it as ranges = <0x02000000 0x0 0xC0000000 0xC0000000 0x0 0x20000000 0x01000000 0x0 0x00000000 0xB8000000 0x0 0x00100000>; I wasn't sure how to reserve the memory (based on your earlier suggestion), so I just narrowed the window. Note that I did not change the PCI hardware registers (maybe the FSL code does?), so the outbound window should still be the whole 512MB. If this isn't viable, perhaps you could explain a bit more how to reserve such a chunk of memory so that the PCI mappings remain the same. Thanks again -- ------------------------------------------------------------ Gary Thomas | Consulting for the MLB Associates | Embedded world ------------------------------------------------------------