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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 22605C54EBC for ; Thu, 12 Jan 2023 11:32:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=0jxlsPcaA56AlQfVlVcC5GtXqoAX7+EP8O3lSQu+52k=; b=Nn53AfBRFiM+yb RYorjAGsd6wRy4prPtmSTBtq/cLT/hlhKS3SOvJgR7dbPYgyMkOMsnd7CRni7SD1GAMtrNe2nVG78 4YKhkWJ+e3PNhX03NaTm4J6u8BZhCFXzl0tY4EgQwCN6e0ir3Y+C1MmePX2rR467T+3aqkZLf42Jp uDX3uUMHmrStfzjO1aLqe4GZJgeEaf5op4cCTXKQ9WOEb533mp12vZhhVYq1jAUM0LO9Yd6j29I9L VbOAna1prWjjGkOuWA8X1tMyUPsn01JTN3plqOssuPb+r8VAGGZB/IDL9V2HD/iHOpsmBUlE6fgE6 KQNvakFPhDAoA0rCKtzg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pFvnl-00EqEw-Jj; Thu, 12 Jan 2023 11:31:21 +0000 Received: from mail-ej1-x62a.google.com ([2a00:1450:4864:20::62a]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pFvnW-00EqC7-V0 for linux-arm-kernel@lists.infradead.org; Thu, 12 Jan 2023 11:31:11 +0000 Received: by mail-ej1-x62a.google.com with SMTP id v6so995843ejg.6 for ; Thu, 12 Jan 2023 03:31:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=OMuAyOi3tfWlxGzLyr9WZRzvZr9Bx2UzbGUycZVDQqY=; b=q2tr9HM5VxAlb2mwHwciq3gjRse0GjE0+vDhDI8zP3Zcb2njpROrPv2SY9bxIJ3krP RmqYW07g5BKQApBoUJN6+Nw7pagjCanKvHHDMgAdibHtiIPB8J9vvTjhvzR/bqBbcI2P CQakZdJEf7AmWhA0PDSMH1ymuVKuZIFPmga5JT5LE48uFzspo+G1A6vhUrXXJ4gvBlhw AfqqgTopEvMZ5QLo3ABdN15CUv26nOirfhe/uFSRPyE9Gme5BnuFRtYH+oJW9v+rWnhQ ogSUXBKhEnF3HKDlj08efs31mh+wmJ7/3MrlbL5VqHFr6yBJUxSWoc0hff5K0chk+jqI PB5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OMuAyOi3tfWlxGzLyr9WZRzvZr9Bx2UzbGUycZVDQqY=; b=VR1W/mqBhAW0YU14KNpA67PJ4fgNx6ZDmTuD7pg8KKiO9My3alqX8yENUdqWY+/ExW KNGpYtN+s5ffxmG1m/xBjWs0MFkFlf903zaiZKiM9+3fpZBPXxb/ZmRvgjBIyrTQWMI/ qA+3P5TINwXWnSh+WZ9/RGPFCbfoX14VQrYjBJ4J+kAbwtyuxx4eWeyH6nYSnazNxHge f3ErfeE89+Ke/V7Q5sxVxZfQdQp8H8rMUm5Dm4N9CAkX1v4ljXSXWD/UfAweOOCAObYW qec1IWOJ8qE8zPuFDgnsjkh/RS6dfeLmLs7sALw4H/r622bHGkf2szvacQh9LCMaea1e qq3w== X-Gm-Message-State: AFqh2krNwzpclYwHdWb6n5iWiln30+L4t61tisf38w6+kiKbQdmyWjqf 96pWjbgv4PEjVykaorf3db5RKQ== X-Google-Smtp-Source: AMrXdXu8nq7pgkBL5G94fORkKbl1bwAxN1S0t3Ainvx6uqRt5geVVuxRrObSl7eTbW+NVr/UGxJBLA== X-Received: by 2002:a17:906:30d4:b0:7a6:5b50:a32c with SMTP id b20-20020a17090630d400b007a65b50a32cmr60646950ejb.12.1673523064627; Thu, 12 Jan 2023 03:31:04 -0800 (PST) Received: from [192.168.1.109] ([178.197.216.144]) by smtp.gmail.com with ESMTPSA id r18-20020a1709061bb200b0082000f8d871sm7362044ejg.152.2023.01.12.03.31.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Jan 2023 03:31:04 -0800 (PST) Message-ID: Date: Thu, 12 Jan 2023 12:31:01 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v2 1/5] PM: domains: Add GENPD_FLAG_RT_SAFE for PREEMPT_RT Content-Language: en-US To: Sebastian Andrzej Siewior Cc: "Rafael J. Wysocki" , Len Brown , Pavel Machek , Greg Kroah-Hartman , Kevin Hilman , Ulf Hansson , Daniel Lezcano , Lorenzo Pieralisi , Sudeep Holla , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Adrien Thierry , Brian Masney , linux-rt-users@vger.kernel.org References: <20221219151503.385816-1-krzysztof.kozlowski@linaro.org> <20221219151503.385816-2-krzysztof.kozlowski@linaro.org> From: Krzysztof Kozlowski In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230112_033107_030634_5C50CEA6 X-CRM114-Status: GOOD ( 27.18 ) 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="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gMTIvMDEvMjAyMyAxMTozMiwgU2ViYXN0aWFuIEFuZHJ6ZWogU2lld2lvciB3cm90ZToKPiBP biAyMDIyLTEyLTE5IDE2OjE0OjU5IFsrMDEwMF0sIEtyenlzenRvZiBLb3psb3dza2kgd3JvdGU6 Cj4+IFJlYWx0aW1lIGtlcm5lbHMgd2l0aCBQUkVFTVBUX1JUIG11c3QgdXNlIHJhd19zcGlubG9j a190IGZvciBkb21haW5zCj4+IHdoaWNoIGFyZSBpbnZva2VkIGZyb20gQ1BVIGlkbGUgKHRodXMg ZnJvbSBhdG9taWMgc2VjdGlvbikuICBFeGFtcGxlIGlzCj4+IGNwdWlkbGUgUFNDSSBkb21haW4g ZHJpdmVyIHdoaWNoIGl0c2VsZiBpcyBQUkVFTVBUX1JUIHNhZmUsIGJ1dCBpcyBiZWluZwo+PiBj YWxsZWQgYXMgcGFydCBvZiBjcHVpZGxlLgo+IAo+IEkgdGhpbmsgaXQgbmVlZHMgdG8gYmUgY2xh cmlmaWVkIHdoYXQgUFJFRU1QVF9SVCBzYWZlIG1lYW5zLiAKCk9LCgo+IFBTQ0kgaXMgYW4KPiBl eHRlcm5hbCBpbnRlcmZhY2Ugd2hpY2ggZG9lcyBub3QgaW5mb3JtIHVzIHdoYXQgaXQgZG9lcyBh bmQgaG93IGxvbmcKPiB0aGUgb3BlcmF0aW9uIHdpbGwgdGFrZS4KPiBUaGUgQUNQSSB0YWJsZSBm b3IgaW5zdGFuY2UgcG9wdWxhdGUgc2V2ZXJhbCBpZGxlIHN0YXRlcyBhbmQgdGhlaXIKPiBlbnRy eS9leGl0IHRpbWUuIFRoZW4geW91IGNhbiBkZWNpZGUgaWYgYW5kIHdoZW4gYW4gZW50cnkvZXhp dCBsYXRlbmN5Cj4gb2YgNTAwdXMgaXMgUFJFRU1QVF9SVCBzYWZlLgo+IAo+PiBBZGQgYSBmbGFn IGFsbG93aW5nIGEgcG93ZXIgZG9tYWluIHByb3ZpZGVyIHRvIGluZGljYXRlIGl0IGlzIFJUIHNh ZmUuCj4+IFRoZSBmbGFnIGlzIHN1cHBvc2VkIHRvIGJlIHVzZWQgd2l0aCBleGlzdGluZyBHRU5Q RF9GTEFHX0lSUV9TQUZFLgo+Pgo+PiBDYzogQWRyaWVuIFRoaWVycnkgPGF0aGllcnJ5QHJlZGhh dC5jb20+Cj4+IENjOiBCcmlhbiBNYXNuZXkgPGJtYXNuZXlAcmVkaGF0LmNvbT4KPj4gQ2M6IGxp bnV4LXJ0LXVzZXJzQHZnZXIua2VybmVsLm9yZwo+PiBTaWduZWQtb2ZmLWJ5OiBLcnp5c3p0b2Yg S296bG93c2tpIDxrcnp5c3p0b2Yua296bG93c2tpQGxpbmFyby5vcmc+Cj4+Cj4g4oCmCj4+IGlu ZGV4IDFjZDQxYmRmNzNjZi4uMGExNjAwMjQ0OTYzIDEwMDY0NAo+PiAtLS0gYS9pbmNsdWRlL2xp bnV4L3BtX2RvbWFpbi5oCj4+ICsrKyBiL2luY2x1ZGUvbGludXgvcG1fZG9tYWluLmgKPj4gQEAg LTYxLDYgKzYxLDE0IEBACj4+ICAgKiBHRU5QRF9GTEFHX01JTl9SRVNJREVOQ1k6CUVuYWJsZSB0 aGUgZ2VucGQgZ292ZXJub3IgdG8gY29uc2lkZXIgaXRzCj4+ICAgKgkJCQljb21wb25lbnRzJyBu ZXh0IHdha2V1cCB3aGVuIGRldGVybWluaW5nIHRoZQo+PiAgICoJCQkJb3B0aW1hbCBpZGxlIHN0 YXRlLgo+PiArICoKPj4gKyAqIEdFTlBEX0ZMQUdfUlRfU0FGRToJCVdoZW4gdXNlZCB3aXRoIEdF TlBEX0ZMQUdfSVJRX1NBRkUsIHRoaXMgaW5mb3Jtcwo+PiArICoJCQkJZ2VucGQgdGhhdCBpdHMg YmFja2VuZCBjYWxsYmFja3MsIC0+cG93ZXJfb258b2ZmKCksCj4+ICsgKgkJCQlkbyBub3QgdXNl IG90aGVyIHNwaW5sb2Nrcy4gVGhleSBtaWdodCB1c2UKPj4gKyAqCQkJCXJhd19zcGlubG9ja3Mg b3Igb3RoZXIgcHJlLWVtcHRpb24tZGlzYWJsZQo+PiArICoJCQkJbWV0aG9kcywgYWxsIG9mIHdo aWNoIGFyZSBQUkVFTVBUX1JUIHNhZmUuIE5vdGUKPiAKPiBQbGVhc2UgdXNlIHNwaW5sb2NrX3Qg YW5kIHJhd19zcGlubG9ja190LiBXb3VsZG4ndCBpdCBiZSBiZXR0ZXIgdG8gd3JpdGUKPiAicHJl ZW1wdGlvbiIgaW5zdGVhZCAicHJlLWVtcHRpb24iPwoKU3VyZS4KCj4gVGhlIGltcG9ydGFudCBw YXJ0IGlzIHByb2JhYmx5IHRoYXQgb25jZSBhIHJhd19zcGlubG9ja190IGhhcyBiZWVuCj4gYWNx dWlyZWQsIGl0IGlzIG5vdCBwb3NzaWJsZSB0byBpbnZva2UgYW55IGZ1bmN0aW9uIHRoYXQgYWNx dXJpZXMKPiBzbGVlcGluZyBsb2NrcyAod2hpY2ggaW5jbHVkZXMgbWVtb3J5IGFsbG9jYXRpb25z KS4gV2hpbGUgZXZlbiB3aXRob3V0Cj4gdGhhdCBmbGFnIGl0IGlzIHBvc3NpYmxlIHRvIGludm9r ZSBhIGZ1bmN0aW9uIHdoaWNoIGRpc2FibGVzIGFuZCBlbmFibGVzCj4gcHJlZW1wdGlvbiBvbiBp dHMgb3duLgo+IAo+PiArICoJCQkJdGhhdCwgYSBnZW5wZCBoYXZpbmcgdGhpcyBmbGFnIHNldCwg cmVxdWlyZXMgaXRzCj4+ICsgKgkJCQltYXN0ZXJkb21haW5zIHRvIGFsc28gaGF2ZSBpdCBzZXQu Cj4gCj4gVGhpcyBjb3VsZCBiZSB2ZXJpZmllZCB1cG9uIHJlZ2lzdHJhdGlvbiwgbm8/CgpJdCBp cywganVzdCBsaWtlIHRoZSBJUlFfU0FGRSBmbGFnLiBUaGUgY29kZSBpcyBzeW1tZXRyaWNhbCB0 byBJUlFfU0FGRS4KCj4gSXQgbWlnaHQgYmUgd29ydGggbm90aW5nIHRoYXQgcHJlZW1wdGlvbi1v ZmYgc2VjdGlvbiBkdXJpbmcgUE0KPiBvcGVyYXRpb25zIGNvbnRyaWJ1dGUgdG8gdGhlIHN5c3Rl bSdzIG1heCBsYXRlbmN5LgoKWW91IG1lYW4gaW4gdGhlIGNvbW1pdCBtc2c/IEluIHRoZSBkb2Ms IEkgZG9uJ3Qgd2FudCB0byBkZXZpYXRlIGZyb20KSVJRX1NBRkUuIEl0J3Mgbm90IHJlYWxseSBy ZWxhdGVkIHRvIHRoZSBmbGFnLgoKPiBEZXBlbmRpbmcgb24gaG93IGxvdwo+IHRoZSBvcGVyYXRp b24gaXMsIGl0IG1heSBvciBtYXkgbm90IGJlIGEgcHJvYmxlbS4KPiBUaGUgLT5wb3dlcl9vbnxv ZmYoKSByZWZlcnMgdG8gdGhlIHNhdGUgb2YgdGhlIGNvbXBvbmVudCwgcmlnaHQ/CgpJdCByZWZl cnMgdG8gZ2VucGQgZnJhbWV3b3JrLgoKQmVzdCByZWdhcmRzLApLcnp5c3p0b2YKCgpfX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpsaW51eC1hcm0ta2VybmVs IG1haWxpbmcgbGlzdApsaW51eC1hcm0ta2VybmVsQGxpc3RzLmluZnJhZGVhZC5vcmcKaHR0cDov L2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5mby9saW51eC1hcm0ta2VybmVsCg== 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A558FC54EBD for ; Thu, 12 Jan 2023 11:41:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233565AbjALLlj (ORCPT ); Thu, 12 Jan 2023 06:41:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50702 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236400AbjALLkr (ORCPT ); Thu, 12 Jan 2023 06:40:47 -0500 Received: from mail-ej1-x62c.google.com (mail-ej1-x62c.google.com [IPv6:2a00:1450:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 077A452773 for ; Thu, 12 Jan 2023 03:31:06 -0800 (PST) Received: by mail-ej1-x62c.google.com with SMTP id v6so995842ejg.6 for ; Thu, 12 Jan 2023 03:31:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=OMuAyOi3tfWlxGzLyr9WZRzvZr9Bx2UzbGUycZVDQqY=; b=q2tr9HM5VxAlb2mwHwciq3gjRse0GjE0+vDhDI8zP3Zcb2njpROrPv2SY9bxIJ3krP RmqYW07g5BKQApBoUJN6+Nw7pagjCanKvHHDMgAdibHtiIPB8J9vvTjhvzR/bqBbcI2P CQakZdJEf7AmWhA0PDSMH1ymuVKuZIFPmga5JT5LE48uFzspo+G1A6vhUrXXJ4gvBlhw AfqqgTopEvMZ5QLo3ABdN15CUv26nOirfhe/uFSRPyE9Gme5BnuFRtYH+oJW9v+rWnhQ ogSUXBKhEnF3HKDlj08efs31mh+wmJ7/3MrlbL5VqHFr6yBJUxSWoc0hff5K0chk+jqI PB5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=OMuAyOi3tfWlxGzLyr9WZRzvZr9Bx2UzbGUycZVDQqY=; b=Lt5auZyUDbTDWyP2atD86xaRZdwo62+EcAdZKPF0L+1fBTKNNYEVNKyNdyx0RcTfyZ QZ8iIpAAEXKtAL5rHlcpdUSMEaCEz+koH7PHf1YMC6IRzqAMXCfq0BYrzFGykyyGgqTs bk8sFY0oy2D/CLuXY2UlshdFCrl2vsyD1ZApumGHQbrJiTh0vgJXhsfCcsiY4pjBIo6a 5nCgQGMaLTcgk/iRhCPQAWChvfAZXhRKpWZ8vpoMKAKz6IcWrcKJOCj+pn1zHPb7aLUV HNAjceA1RCKA7DdAKKkxUb/iaEe5FKRa47qmOiZXLyMp3C9mfo0Lbxg8SFG1PK7Qdlyv 794g== X-Gm-Message-State: AFqh2kpxY18vibc80R6/SDNkA33pfYT+7Urx3PMgUD4ta/AUyr6k1AYE X76ylfaF0Xftp+WuWcSJqvtlDA== X-Google-Smtp-Source: AMrXdXu8nq7pgkBL5G94fORkKbl1bwAxN1S0t3Ainvx6uqRt5geVVuxRrObSl7eTbW+NVr/UGxJBLA== X-Received: by 2002:a17:906:30d4:b0:7a6:5b50:a32c with SMTP id b20-20020a17090630d400b007a65b50a32cmr60646950ejb.12.1673523064627; Thu, 12 Jan 2023 03:31:04 -0800 (PST) Received: from [192.168.1.109] ([178.197.216.144]) by smtp.gmail.com with ESMTPSA id r18-20020a1709061bb200b0082000f8d871sm7362044ejg.152.2023.01.12.03.31.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Jan 2023 03:31:04 -0800 (PST) Message-ID: Date: Thu, 12 Jan 2023 12:31:01 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v2 1/5] PM: domains: Add GENPD_FLAG_RT_SAFE for PREEMPT_RT Content-Language: en-US To: Sebastian Andrzej Siewior Cc: "Rafael J. Wysocki" , Len Brown , Pavel Machek , Greg Kroah-Hartman , Kevin Hilman , Ulf Hansson , Daniel Lezcano , Lorenzo Pieralisi , Sudeep Holla , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Adrien Thierry , Brian Masney , linux-rt-users@vger.kernel.org References: <20221219151503.385816-1-krzysztof.kozlowski@linaro.org> <20221219151503.385816-2-krzysztof.kozlowski@linaro.org> From: Krzysztof Kozlowski In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/01/2023 11:32, Sebastian Andrzej Siewior wrote: > On 2022-12-19 16:14:59 [+0100], Krzysztof Kozlowski wrote: >> Realtime kernels with PREEMPT_RT must use raw_spinlock_t for domains >> which are invoked from CPU idle (thus from atomic section). Example is >> cpuidle PSCI domain driver which itself is PREEMPT_RT safe, but is being >> called as part of cpuidle. > > I think it needs to be clarified what PREEMPT_RT safe means. OK > PSCI is an > external interface which does not inform us what it does and how long > the operation will take. > The ACPI table for instance populate several idle states and their > entry/exit time. Then you can decide if and when an entry/exit latency > of 500us is PREEMPT_RT safe. > >> Add a flag allowing a power domain provider to indicate it is RT safe. >> The flag is supposed to be used with existing GENPD_FLAG_IRQ_SAFE. >> >> Cc: Adrien Thierry >> Cc: Brian Masney >> Cc: linux-rt-users@vger.kernel.org >> Signed-off-by: Krzysztof Kozlowski >> > … >> index 1cd41bdf73cf..0a1600244963 100644 >> --- a/include/linux/pm_domain.h >> +++ b/include/linux/pm_domain.h >> @@ -61,6 +61,14 @@ >> * GENPD_FLAG_MIN_RESIDENCY: Enable the genpd governor to consider its >> * components' next wakeup when determining the >> * optimal idle state. >> + * >> + * GENPD_FLAG_RT_SAFE: When used with GENPD_FLAG_IRQ_SAFE, this informs >> + * genpd that its backend callbacks, ->power_on|off(), >> + * do not use other spinlocks. They might use >> + * raw_spinlocks or other pre-emption-disable >> + * methods, all of which are PREEMPT_RT safe. Note > > Please use spinlock_t and raw_spinlock_t. Wouldn't it be better to write > "preemption" instead "pre-emption"? Sure. > The important part is probably that once a raw_spinlock_t has been > acquired, it is not possible to invoke any function that acquries > sleeping locks (which includes memory allocations). While even without > that flag it is possible to invoke a function which disables and enables > preemption on its own. > >> + * that, a genpd having this flag set, requires its >> + * masterdomains to also have it set. > > This could be verified upon registration, no? It is, just like the IRQ_SAFE flag. The code is symmetrical to IRQ_SAFE. > It might be worth noting that preemption-off section during PM > operations contribute to the system's max latency. You mean in the commit msg? In the doc, I don't want to deviate from IRQ_SAFE. It's not really related to the flag. > Depending on how low > the operation is, it may or may not be a problem. > The ->power_on|off() refers to the sate of the component, right? It refers to genpd framework. Best regards, Krzysztof