From patchwork Tue Oct 19 16:35:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Lezcano X-Patchwork-Id: 12570599 X-Patchwork-Delegate: daniel.lezcano@linaro.org 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE779C433EF for ; Tue, 19 Oct 2021 16:35:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A554C6135E for ; Tue, 19 Oct 2021 16:35:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231526AbhJSQhf (ORCPT ); Tue, 19 Oct 2021 12:37:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232130AbhJSQhf (ORCPT ); Tue, 19 Oct 2021 12:37:35 -0400 Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com [IPv6:2a00:1450:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45449C061768 for ; Tue, 19 Oct 2021 09:35:22 -0700 (PDT) Received: by mail-wm1-x329.google.com with SMTP id y74-20020a1c7d4d000000b00322f53b9bbfso3827337wmc.3 for ; Tue, 19 Oct 2021 09:35:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=6lGbUk9scuSolc0mMC7O3O5jKEdhtvYf+nI62abO4j4=; b=ppRTjWSzYtJqN0FzfUhvG4tLw/33KSdRGOXyf0A972B6B9Qqo8wsj6RBVzmuuqb/wW GwNSwmXgm9JVb512/caLZjdGQeYjwLQJpKqRkxTPjAXApdz0Jj8cG6gPgzIzibmQ4LPb VDMb35EslXmp7JmscSylFEmQY60WdVrn4uOIZ3AZXnt7nFCqcHV58xzIocbGEZMkAcOx sGwcWTkiQtLyDJ23NKScPp5QxBFih7YB0A6Xbq7YnDhZOryF3SFot24TLJB2LMzJOPWB r3+3xQozGKC7oswJO0f2E98ameFHg+zigQHiyvRqraVCu60IP7tBnXyHDqauaDVY2qZC 13Jg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=6lGbUk9scuSolc0mMC7O3O5jKEdhtvYf+nI62abO4j4=; b=y9i/J9w4T9/8D84nnbI6En2YOSmylgL+KQVuD/FZtMCEsEql2f5oLiab3HhSr86dBQ /dXj4m5JwkhVJ96uubXxZj8NjpfvpG695oWxP48p30ZHJyWleaWvALZykjXqMpdv03zp A1DWvmnbqN0oh7JBpJ/n3rk5ILYacVL3WQXIIYqyB6n1Z1k0Op1SRByOLSiyI46fNdOO Nnj2O5748RlKBqzTSTSc9ry07I/xR7RmGMwV+X6BF4z3/ho5c6HWNFVxlLySygvR2JLF 9HKB7Lk3l51MYNXHbwpUa15ogHFlG/THBOlhbKsV10f+qJbMt9b/eZBjov6RVI2nTtq6 3CUw== X-Gm-Message-State: AOAM5316fT/g1K6PW0glMvk+hU2KfAJt1VMRRr4QnbOGQ2YYoJxTm7iQ cbV82S3B3ZT4j0Io5WqrQE8uKA== X-Google-Smtp-Source: ABdhPJz4qYyTxSplorxLWlOxOc1azR2uKhPM6L83bGXJ4bXdXMR5I0XYlkeHzwIxpQijTU0pclODLQ== X-Received: by 2002:a7b:c08a:: with SMTP id r10mr7301002wmh.135.1634661320770; Tue, 19 Oct 2021 09:35:20 -0700 (PDT) Received: from localhost.localdomain ([2a01:e34:ed2f:f020:4799:198d:b6ef:8da7]) by smtp.gmail.com with ESMTPSA id n7sm15377389wra.37.2021.10.19.09.35.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Oct 2021 09:35:20 -0700 (PDT) From: Daniel Lezcano To: daniel.lezcano@linaro.org, rjw@rjwysocki.net Cc: lukasz.luba@arm.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Zhang Rui , Amit Kucheria Subject: [PATCH v3 2/2] thermal/core: Deprecate changing cooling device state from userspace Date: Tue, 19 Oct 2021 18:35:06 +0200 Message-Id: <20211019163506.2831454-2-daniel.lezcano@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211019163506.2831454-1-daniel.lezcano@linaro.org> References: <20211019163506.2831454-1-daniel.lezcano@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org The cooling devices have their cooling device set_cur_state read-writable all the time in the sysfs directory, thus allowing the userspace to act on it. The thermal framework is wrongly used by userspace as a power capping framework by acting on the cooling device opaque state. This one then competes with the in-kernel governor decision. We have seen in out-of-tree kernels, a big number of devices which are abusely declaring themselves as cooling device just to act on their power. The role of the thermal framework is to protect the junction temperature of the silicon. Letting the userspace to play with a cooling device is invalid and potentially dangerous. The powercap framework is the right framework to do power capping and moreover it deals with the aggregation via the dev pm qos. As the userspace governor is marked deprecated and about to be removed, there is no point to keep this file writable also in the future. Emit a warning and deprecate the interface. Signed-off-by: Daniel Lezcano Acked-by: Rafael J. Wysocki --- drivers/thermal/thermal_sysfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index 1c4aac8464a7..f154bada2906 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -610,6 +610,9 @@ cur_state_store(struct device *dev, struct device_attribute *attr, unsigned long state; int result; + dev_warn_once(&cdev->device, + "Setting cooling device state is deprecated\n"); + if (sscanf(buf, "%ld\n", &state) != 1) return -EINVAL;