From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A87F3C31E46 for ; Wed, 12 Jun 2019 07:38:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 808DC2080A for ; Wed, 12 Jun 2019 07:38:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LxDh7dzp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 808DC2080A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:Message-ID: In-Reply-To:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=OgHAsME+bBGojbzeCYOCeggDIXFTep+FEAW5FRmsgFA=; b=LxDh7dzplDT9Vg U3NIvRNAAvr9ffCpM86JyqPNQQOUou8nS/gU7gkndr6I2/X/mD6evP4WSFpVO7OG/Lhr5lKKBzSCQ YUJ+qGv9zolGkFH4j4Q4QyMYuPMdb2S3OIwAOuyKGAeLIf/AS2xqlgb9TuBQjIoQz1SG5O4/N8gyO GnJTRn/ojuy0uKgLy52QF5WhP7XEnke5ahxB5hmkMl7sahfGiJ3mEw5hNSJEvCUXATjl95Pj87I1y nWKU5ygmtSk4CtouFTbY02OATl1qCQpnwEBvXRYuvSBI2u1NmY5YDGWliN3fMoaso/jSzZfWMN40m /3AG7YxUCVhbPRTeUXpg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1haxph-0005jK-24; Wed, 12 Jun 2019 07:38:09 +0000 Received: from galois.linutronix.de ([2a01:7a0:2:106d:700::1]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1haxpd-0005iX-1J for linux-arm-kernel@lists.infradead.org; Wed, 12 Jun 2019 07:38:06 +0000 Received: from p5b06daab.dip0.t-ipconnect.de ([91.6.218.171] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1haxpX-0006a0-OZ; Wed, 12 Jun 2019 09:37:59 +0200 Date: Wed, 12 Jun 2019 09:37:58 +0200 (CEST) From: Thomas Gleixner To: Marc Zyngier Subject: Re: [RFC 0/2] Add workaround for core wake-up on IPI for i.MX8MQ In-Reply-To: <86ftofgss2.wl-marc.zyngier@arm.com> Message-ID: References: <20190610121346.15779-1-abel.vesa@nxp.com> <20190610131921.GB14647@lakrids.cambridge.arm.com> <20190610132910.srd4j2gtidjeppdx@fsr-ub1664-175> <6f1052ea-623a-b2e8-9aa8-22aef5fab4ca@arm.com> <20190610135514.xd5myavjsloos2y3@fsr-ub1664-175> <7b86aa90-6d64-589c-f11e-d2ee6ab3fd54@arm.com> <86ftofgss2.wl-marc.zyngier@arm.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190612_003805_224827_E0838B5B X-CRM114-Status: GOOD ( 17.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , "devicetree@vger.kernel.org" , Lorenzo Pieralisi , Abel Vesa , Carlo Caione , Fabio Estevam , Sascha Hauer , "linux-kernel@vger.kernel.org" , Rob Herring , Jacky Bai , dl-linux-imx , Pengutronix Kernel Team , Abel Vesa , Leonard Crestez , Shawn Guo , "linux-arm-kernel@lists.infradead.org" , Lucas Stach Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 12 Jun 2019, Marc Zyngier wrote: > On Wed, 12 Jun 2019 08:14:16 +0100, > Thomas Gleixner wrote: > > On Mon, 10 Jun 2019, Leonard Crestez wrote: > > > On 6/10/2019 5:08 PM, Marc Zyngier wrote: > > > > Nobody is talking about performance here. It is strictly about > > > > correctness, and what I read about this system is that it cannot > > > > reliably use cpuidle. > > > My argument was that it's fine if PPIs and LPIs are broken as long as > > > they're not used: > > > > > > * PPIs are only used for local timer which is not used for wakeup. > > > > Huch? The timer has to bring the CPU out of idle as any other > > interrupt. > > They use a separate hack for that, pretending that the timer is > stopped during idle (it isn't), and setup a broadcast timer when > entering idle. That timer uses an interrupt that can wake-up the > target CPU, and all is well in the world. Sort of. > > Of course, this breaks as PPIs are not only used by the timer, but > also by a number of other HW bits (PMU, GIC, guest and hypervisor > timers), and they don't have corresponding hacks to back them up. Eew. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel