From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 27F36DDE1B for ; Thu, 25 Sep 2008 17:25:43 +1000 (EST) Subject: Re: [PATCH HACK] powerpc: quick hack to get a functional eHEA with hardirq preemption From: Benjamin Herrenschmidt To: Sebastien Dugue 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 Cc: linux-kernel@vger.kernel.org, Milton Miller , linuxppc-dev@ozlabs.org, Christoph Raisch , Paul Mackerras , Jan-Bernd Themann Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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.