Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262637AbVAPWXr (ORCPT ); Sun, 16 Jan 2005 17:23:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262641AbVAPWRA (ORCPT ); Sun, 16 Jan 2005 17:17:00 -0500 Received: from gate.crashing.org ([63.228.1.57]:25542 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S262634AbVAPWPk (ORCPT ); Sun, 16 Jan 2005 17:15:40 -0500 Subject: Re: [PATCH 1/1] pci: Block config access during BIST (resend) From: Benjamin Herrenschmidt To: Andi Kleen Cc: Alan Cox , brking@us.ibm.com, Paul Mackerras , Linux Kernel Mailing List In-Reply-To: <20050116220714.GA76666@muc.de> References: <1105645491.4624.114.camel@localhost.localdomain> <20050113215044.GA1504@muc.de> <1105743914.9222.31.camel@localhost.localdomain> <20050115014440.GA1308@muc.de> <1105750898.9222.101.camel@localhost.localdomain> <1105770012.27411.72.camel@gaston> <1105829883.15835.6.camel@localhost.localdomain> <1105848104.27436.97.camel@gaston> <20050116044823.GA55143@muc.de> <1105908798.27436.102.camel@gaston> <20050116220714.GA76666@muc.de> Content-Type: text/plain Date: Mon, 17 Jan 2005 09:14:18 +1100 Message-Id: <1105913658.27410.107.camel@gaston> Mime-Version: 1.0 X-Mailer: Evolution 2.0.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1067 Lines: 24 On Sun, 2005-01-16 at 23:07 +0100, Andi Kleen wrote: > > What is complex in there ? I agree it's not convenient to do this from > > the very low level ones that don't take the pci_dev * as an argument, > > but from the higher level ones that does, the overhead is basically to > > test a flag in the pci_dev, I doubt it will be significant in any way > > performance wise, especially compared to the cost of a config space > > access... > > For once you cannot block in them. There are even setups that > need to (have to) do config space accesses in interrupt handlers. > The operations done there should be rather light weight. I don't think we ever want to block in that sense. I think all we need is the "filter" mecanism, that is drop writes and return cached data on reads when the device is "offlined"... Ben. - 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/