From nobody Fri Dec 19 14:37:41 2025 Received: from esa11.hc1455-7.c3s2.iphmx.com (esa11.hc1455-7.c3s2.iphmx.com [207.54.90.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5BCC625CC7A; Tue, 20 May 2025 06:28:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=207.54.90.137 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747722507; cv=none; b=l2//ERgC1MivUmwcEgPHttcc2NMqbHqZcnhnIMGFzsMaXyoX1fy6PIxgcrcEFIAVUVWZpfoLlUJjn+IawV0A+rMVO7GefBFX6ad3EZdt2Vde2egbIPOpGN8BxaxbV4YdQgEosR0bcYQyTumW8yLNk9XV2jCBdBvf8YPlgdidWlg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747722507; c=relaxed/simple; bh=atb6z9XN7RCNKDZIpyj4g2de70/OejRuLU3sua0jLJY=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=DK+mRc6yYlsosqyNXyvAhDFppUkSgjygsUh6he9BEYgFi+PGU4oS9iohT5eNRkf25OCyZszRhyMQ8HjG79GRTOhgGd13fyIOiBuzv3Pi+HwxGMKCTxJICJqKEahizIX+9zvqFsWsUtMYbDNfncg7WPDgYsCfbTR1CHz5srA2CKM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fujitsu.com; spf=pass smtp.mailfrom=fujitsu.com; dkim=pass (2048-bit key) header.d=fujitsu.com header.i=@fujitsu.com header.b=sbxkTALx; arc=none smtp.client-ip=207.54.90.137 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fujitsu.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fujitsu.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fujitsu.com header.i=@fujitsu.com header.b="sbxkTALx" DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=fujitsu.com; i=@fujitsu.com; q=dns/txt; s=fj2; t=1747722505; x=1779258505; h=from:to:subject:date:message-id:mime-version: content-transfer-encoding; bh=atb6z9XN7RCNKDZIpyj4g2de70/OejRuLU3sua0jLJY=; b=sbxkTALxEGIfT60slQtcl95iWBamxuAYRDnWAacVK2fPc/eWsRIgmkQl ilBDpnp16ZQcnIb68LdwFDqsZLnOtvbaKZnAjeSUGJ5IvuWATvo/q0ogJ nGUcihAk/UUnJRms5/W3p0zNDdfpOU/MprU7iFN5puoXlTnEmLcCSgxyA KlkQNF/ClOSVKa3/LFJ1R3gfKbtRLtzNcaPC4SClPRwKMIET0hU47gqnd yUEdjtRBfiCWxVO2hsSp+8lHR/GIMr2N3tVsp+79ZrBECLxeuMGhJfbw0 WGxg0bIX9q50Qjmff/lwjgJkWHJrAJadwDmWDeR+muDjg8DGnOXgEZkBA w==; X-CSE-ConnectionGUID: LvLGJodVRRu2qf2agvdBUA== X-CSE-MsgGUID: vpB2GC5QSlqDUko+T+DTZQ== X-IronPort-AV: E=McAfee;i="6700,10204,11438"; a="179514708" X-IronPort-AV: E=Sophos;i="6.15,302,1739804400"; d="scan'208";a="179514708" Received: from unknown (HELO yto-r2.gw.nic.fujitsu.com) ([218.44.52.218]) by esa11.hc1455-7.c3s2.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2025 15:27:15 +0900 Received: from yto-m1.gw.nic.fujitsu.com (yto-nat-yto-m1.gw.nic.fujitsu.com [192.168.83.64]) by yto-r2.gw.nic.fujitsu.com (Postfix) with ESMTP id E5664C68A5; Tue, 20 May 2025 15:27:11 +0900 (JST) Received: from oym-om3.fujitsu.com (oym-om3.o.css.fujitsu.com [10.85.58.163]) by yto-m1.gw.nic.fujitsu.com (Postfix) with ESMTP id B2472CFA2E; Tue, 20 May 2025 15:27:11 +0900 (JST) Received: from sm-arm-grace07.ssoft.mng.com (sm-x86-stp01.soft.fujitsu.com [10.124.178.20]) by oym-om3.fujitsu.com (Postfix) with ESMTP id 5293E4004BB01; Tue, 20 May 2025 15:27:11 +0900 (JST) From: Shinji Nomoto To: Jean Delvare , Guenter Roeck , Jonathan Corbet , linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Shinji Nomoto Subject: [PATCH v2] doc: hwmon: acpi_power_meter: Add information about enabling the power capping feature. Date: Tue, 20 May 2025 15:27:04 +0900 Message-ID: <20250520062707.1657667-1-fj5851bi@fujitsu.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To enable the power capping feature of the acpi_power_meter driver on systems other than IBM products, you must explicitly specify the force_cap_on module parameter. Add information to the documentation about enabling the power capping feature with this driver, including the above, to improve user convenience. ----- Here are the differences from the previous patch: * Added a note to the "Module Parameters" description regarding systems that do not support power capping. The previous post can be found at: https://lore.kernel.org/linux-hwmon/20250519072756.1512244-1-fj5851bi@fujit= su.com/T/#u Signed-off-by: Shinji Nomoto --- Documentation/hwmon/acpi_power_meter.rst | 29 +++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/Documentation/hwmon/acpi_power_meter.rst b/Documentation/hwmon= /acpi_power_meter.rst index 8628c1161015..a91403a2a26f 100644 --- a/Documentation/hwmon/acpi_power_meter.rst +++ b/Documentation/hwmon/acpi_power_meter.rst @@ -37,9 +37,16 @@ arbitrary strings that ACPI provides with the meter. Th= e measures/ directory contains symlinks to the devices that this meter measures. =20 Some computers have the ability to enforce a power cap in hardware. If th= is is -the case, the `power[1-*]_cap` and related sysfs files will appear. When = the -average power consumption exceeds the cap, an ACPI event will be broadcast= on -the netlink event socket and a poll notification will be sent to the +the case, the `power[1-*]_cap` and related sysfs files will appear. +For information on enabling the power cap feature, refer to the description +of the "force_on_cap" option in the "Module Parameters" chapter. +To use the power cap feature properly, you need to set appropriate value +(in microWatts) to the `power[1-*]_cap` sysfs files. +The value must be within the range between the minimum value at `power[1-]= _cap_min` +and the maximum value at `power[1-]_cap_max (both in microWatts)`. + +When the average power consumption exceeds the cap, an ACPI event will be +broadcast on the netlink event socket and a poll notification will be sent= to the appropriate `power[1-*]_alarm` file to indicate that capping has begun, an= d the hardware has taken action to reduce power consumption. Most likely this w= ill result in reduced performance. @@ -52,3 +59,19 @@ follows: `power[1-*]_cap` will be notified if the firmware changes the power cap. `power[1-*]_interval` will be notified if the firmware changes the averagi= ng interval. + +Module Parameters +----------------- + +* force_cap_on: bool + Forcefully enable the power capping feature to spe= cify + the upper limit of the system's power consumption. + + By default, the driver's power capping feature is = only + enabled on IBM products. + Therefore, on other systems that support power cap= ping, + you will need to use the option to enable it. + + Note: power capping is potentially unsafe feature. + Please check the platform specifications to make s= ure + that capping is supported before using this option. --=20 2.43.0