Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754590AbXIPXiX (ORCPT ); Sun, 16 Sep 2007 19:38:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754035AbXIPXiO (ORCPT ); Sun, 16 Sep 2007 19:38:14 -0400 Received: from idcmail-mo1so.shaw.ca ([24.71.223.10]:62429 "EHLO pd4mo1so.prod.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753878AbXIPXiN (ORCPT ); Sun, 16 Sep 2007 19:38:13 -0400 Date: Sun, 16 Sep 2007 17:37:29 -0600 From: Robert Hancock Subject: Re: [PATCH]PCI:disable resource decode in PCI BAR detection In-reply-to: <1189973176.6403.20.camel@localhost.localdomain> To: Benjamin Herrenschmidt Cc: Ivan Kokshaysky , Greg KH , Matthew Wilcox , Shaohua Li , lkml , linux-pci , Andrew Morton Message-id: <46EDBE39.4090704@shaw.ca> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8; format=flowed Content-transfer-encoding: 7bit References: <46EA00DA.6010704@shaw.ca> <1189973176.6403.20.camel@localhost.localdomain> User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1483 Lines: 35 Benjamin Herrenschmidt wrote: > On Thu, 2007-09-13 at 21:32 -0600, Robert Hancock wrote: >> If we do encounter other devices that choke on having the BAR >> disabled >> during probing then we can add additional quirk logic, but we haven't >> run into anything like that yet. > > Well... if the device needs to be accessed to service an interrupt then > you do have a problem. For example... the PIC :-) > > Problem is.. it's not practical nor really feasible generally to have > IRQs off on all CPUs during PCI probing neither... Unless we define that > the initial boot time probing is "special", and the first pass that > actually probes devices (and doesn't muck around with the sysfs > hierarchy etc...) can be run in a special context with all interrupt > servicing disabled on the PIC, though that will require some arch > support. > > Ben. We would already have this problem, though. If it causes problems to disable decode on the BAR because we try to access it in interrupt context, we would already have problems because we move the thing to 0xFFFFFFFF during probing anyway.. -- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@nospamshaw.ca Home Page: http://www.roberthancock.com/ - 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/