Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262528AbVA0BGK (ORCPT ); Wed, 26 Jan 2005 20:06:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262464AbVA0APy (ORCPT ); Wed, 26 Jan 2005 19:15:54 -0500 Received: from gate.crashing.org ([63.228.1.57]:43478 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S262471AbVAZWLW (ORCPT ); Wed, 26 Jan 2005 17:11:22 -0500 Subject: Re: [PATCH 1/1] pci: Block config access during BIST (resend) From: Benjamin Herrenschmidt To: brking@us.ibm.com Cc: Alan Cox , Andi Kleen , Paul Mackerras , Linux Kernel Mailing List In-Reply-To: <41F7C6A1.9070102@us.ibm.com> References: <200501101449.j0AEnWYF020850@d03av01.boulder.ibm.com> <41E2AC74.9090904@us.ibm.com> <20050110162950.GB14039@muc.de> <41E3086D.90506@us.ibm.com> <1105454259.15794.7.camel@localhost.localdomain> <20050111173332.GA17077@muc.de> <1105626399.4664.7.camel@localhost.localdomain> <20050113180347.GB17600@muc.de> <1105641991.4664.73.camel@localhost.localdomain> <20050113202354.GA67143@muc.de> <41ED27CD.7010207@us.ibm.com> <1106161249.3341.9.camel@localhost.localdomain> <41F7C6A1.9070102@us.ibm.com> Content-Type: text/plain Date: Thu, 27 Jan 2005 09:10:05 +1100 Message-Id: <1106777405.5235.78.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: 1190 Lines: 28 On Wed, 2005-01-26 at 10:34 -0600, Brian King wrote: > Here is the last one. I've looked at making userspace sleep until BIST > is finished. The downside I see to this is that is complicates the patch > due to the following reasons: > > 1. In order to also make this work for Ben's PPC power management usage > would require an additional flag and additional APIs to set and clear > the flag. > 2. Since BIST can be run at interrupt context, the interfaces to block > and unblock userspace accesses across BIST must be callable from > interrupt context. This prevents the usage of semaphores or simple > wait_event macros and requires new macros that carefully check the new > pci device flag and manage the spinlock. > Well, I honestly think that this is unnecessary burden. I think that just dropping writes & returning data from the cache on reads is enough, blocking userspace isn't necessary, but then, I may be wrong ;) 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/