From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753216AbYIYHZ4 (ORCPT ); Thu, 25 Sep 2008 03:25:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752047AbYIYHZr (ORCPT ); Thu, 25 Sep 2008 03:25:47 -0400 Received: from gate.crashing.org ([63.228.1.57]:36003 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751841AbYIYHZq (ORCPT ); Thu, 25 Sep 2008 03:25:46 -0400 Subject: Re: [PATCH HACK] powerpc: quick hack to get a functional eHEA with hardirq preemption From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: Sebastien Dugue Cc: Milton Miller , Jan-Bernd Themann , Christoph Raisch , Paul Mackerras , linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org In-Reply-To: <20080925091827.29b5087c@bull.net> References: <200809231743.23828.ossthema@de.ibm.com> <20080915100406.342e027a@bull.net> <200809240958.m8O9wM7k010996@sullivan.realtime.net> <1222251467.8277.73.camel@pasglop> <20080924143552.29a14f10@bull.net> <1222290917.8277.83.camel@pasglop> <20080925091827.29b5087c@bull.net> Content-Type: text/plain Date: Thu, 25 Sep 2008 17:22:41 +1000 Message-Id: <1222327361.8277.179.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2008-09-25 at 09:18 +0200, Sebastien Dugue wrote: > > > Ok, that's the right approach then. It should work. I don't know > what > > the specific problems with HEA are at this stage. > > Yep, except as it behaves in way that the current -rt fasteoi flow > cannot handle. We probably need to make a special xics flow handler for -rt that does what Milton suggested, ie, bring down the CPU priority right away and only EOI later or something like that, instead of masking/unmasking. I don't know what are the other potential issues with the HEA though. Ben.