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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 3DB25C433ED for ; Tue, 20 Apr 2021 14:20:55 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 BE6ED613AF for ; Tue, 20 Apr 2021 14:20:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE6ED613AF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc: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=A0XLjP/09HrWA8Lo4xWWf1Fgb5/DxjJlocUzz7OmIv8=; b=iWWZTErX1EobQSWdWwdz5O+NW dCL/yJQENVS9eiTQEPpWMjVAASsx3U2GFQTXZNtJXIQ21xhb6+EaicI6RZLeSHSQPI4+zJUjr9fZ4 9pQ7zE9OGvIpR/C+4Prs+IVHOJrNrr3mpFJP2acPHrEUEjr4FpuFqElTWKOTNbem3mtip+ZIebRwg 0DXBu/p+7BQyp/k5HuS0gYlsYDQHY6F50FM7OZTp4849jGVO9YxqFIIhr5wpLgdrsVE72LWfYhgBM NdS6NAw8wajBzSAbEIMEv4HivRJCKQu7mg2IVJbzxFqmtaqvpiD45ND3WNubmRRMs3PWGXbKku6zV 7Wk0CFRqA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lYrDX-00CK7k-MQ; Tue, 20 Apr 2021 14:19:07 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lYrDU-00CK7R-4S for linux-arm-kernel@desiato.infradead.org; Tue, 20 Apr 2021 14:19:04 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=FaALT2JVqPv7L4+batO+xZaaaT0pTBh42l6l55S6wq4=; b=FohNFZazv9pp5Y6o0wNAk6XTs+ zTzMsROwmhRSoZfEEfEP9O/6DUF4yBh+C1ek0E6KBYAn1k55ZeMJplvrb7tusDDXVIb6INEpRzQtV wQlkrt0nXtVv7cnHb5WCkHgpKc+rzF2yOqgkQ5EbN0gIOtEYIKHtCT6iQiUooADBGpA6NqwTha50O IdhdNzt6jMaRY/elDlyi5Unw9G72FZ3XMIotzJC0eWV+b+8fj1MNfc8q1RzlsY74ns/rmfndluXLY QWhZzZBuMKKB2jddPT22w/wMg364O9+LhPdAW/uWtmik+XCbGLG39iR/DDH66jSEyfLgK1jDpDMD5 qyQ6zRDQ==; Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lYrDP-00CBcr-Kh for linux-arm-kernel@lists.infradead.org; Tue, 20 Apr 2021 14:19:02 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 711B41478; Tue, 20 Apr 2021 07:18:50 -0700 (PDT) Received: from bogus (unknown [10.57.52.142]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7B5873F792; Tue, 20 Apr 2021 07:18:49 -0700 (PDT) Date: Tue, 20 Apr 2021 15:18:47 +0100 From: Sudeep Holla To: Michael Tretter Cc: Rajan Vaja , Sudeep Holla , "linux-arm-kernel@lists.infradead.org" , Michal Simek , Jolly Shah Subject: Re: [PATCH 0/4] soc: xilinx: pm_domains: cleanup and fix PM_INIT_FINALIZE Message-ID: <20210420141847.blcjrrvekjt6llck@bogus> References: <20210317160410.2097178-1-m.tretter@pengutronix.de> <20210419073239.GA12636@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210419073239.GA12636@pengutronix.de> User-Agent: NeoMutt/20171215 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210420_071859_751310_3867E9CA X-CRM114-Status: GOOD ( 17.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Apr 19, 2021 at 09:32:39AM +0200, Michael Tretter wrote: Sorry for chiming in randomly. I always though the way PM_INIT_FINALIZE is designed has issues(e.g. racy). I was involved in discussion with Xilinx when we will designing more generic version of EEMI - SCMI which is now supported in upstream. EEMI was in production already when we started on SCMI 3-4 years back and wanted to get feedback. [...] > > What is the reason why all devices have to be requested before calling > zynqmp_pm_init_finalize()? > Yes that is wrong assumption/expectation from the firmware. > I was expecting that calling PM_INIT_FINALIZE only would tell the PMU_FW that > Linux is using the PM API and the PMU_FW should power down/up PM slaves as > requested by Linux. It is somewhat surprising that this isn't the case and all > PM slaves have to be powered up before calling PM_INIT_FINALIZE. > Agreed that was my understanding too. > What would happen if some driver is built as a module? In that case, the > module would be loaded and request the pm node only after PM_INIT_FINALIZE was > called. Do we have to avoid/disallow such cases? > I was told it will work. But it will be always racy if there are multiple channels to talk to firmware. My argument firmware can turn off all the devices before giving control to OS and no need for that. But there is some boot time optimisation possible I am told which I could well be. But this interface for too racy IMO, just happens to be fine with limited configurations it operates in. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel