From patchwork Tue Aug 11 14:57:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 11709301 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0053B13B1 for ; Tue, 11 Aug 2020 14:57:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDD9820782 for ; Tue, 11 Aug 2020 14:57:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cW36UHO4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728801AbgHKO5M (ORCPT ); Tue, 11 Aug 2020 10:57:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728802AbgHKO5M (ORCPT ); Tue, 11 Aug 2020 10:57:12 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54360C06174A for ; Tue, 11 Aug 2020 07:57:12 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id t10so6924359plz.10 for ; Tue, 11 Aug 2020 07:57:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id; bh=HiRyyvPWTm8b2GQeXXjpsfAovyJaui0eVELYWeqdZUk=; b=cW36UHO4Gup4UNNIFjGJayEXDnAASuM0vq9VvzLILhqyVF7rAx4XAKpwiqSY0jNWKz GJxmsj339VwraLgT+IxMLNN0fyLJWW3Yw1vQ4kKIojVASX3M6i9QyFplfXgvE/Pd5i8V t84IEFW++AorrHU+uQRbz+P+nhIHFntEF45FCPZR8Lv4rV01xjRqhTeAfp+X/ALKwIsf et2t/v0uNh4j2CQBD5o0hF8YzYt/Vm1MPtEVftizj3gi/a8MmrVVLG3j9sJMVMG7LkKL 9ESJX1LcO43Vs2wMHLcVbDbbi4mUp0EBoZnw84fpsM7/W5e6yhbxN0wnXHh3kj81GShE 7cyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id; bh=HiRyyvPWTm8b2GQeXXjpsfAovyJaui0eVELYWeqdZUk=; b=YKT6sbYwfiWs7HlxqD26FGGhRjApNiYy4JdS0KkH8VHPQru0ruGusJYAKYd5At11oP zmUp8khzh7mORTGOGVRRsb88UwqGS2NUvMSFxHBWGa2WYpZpGA+yczb8cgp8NPZ7SoMw W498geFAkPFP6W0uWtA9UhuZI9ACuWEC+Y3cATwIx+bwL3Y/CS3gwxQigCZKLWqVKLnb nvnYttulF/Qq4Z3z75yMiAZlcQWzgHocgDk1zZJzPabckIPxAlNBC+iPvtHr27IzFgh+ fdm3nASW2rtpQMTT9Qp59kC1m3n4Z2VX6bUV6kugAauEUEkYIJMr8+ZRX1q25MzyLCnz bKyQ== X-Gm-Message-State: AOAM533QTc7JQcMdbBL4RYTehYte8l7yRkVvRbkudQ0TMQbN4HmDmvde sZR5Rh23n8trBQqOouvPo0MOX11X X-Google-Smtp-Source: ABdhPJwwwACHgJUW8oO9/ezJ7AitNAfOTwy66kahSJSDE67ZebRbi7GEty3JcVbxTlvLwY9vspAKSg== X-Received: by 2002:a17:90a:e107:: with SMTP id c7mr1513960pjz.100.1597157831568; Tue, 11 Aug 2020 07:57:11 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id f77sm27344976pfa.216.2020.08.11.07.57.10 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 11 Aug 2020 07:57:11 -0700 (PDT) From: Guenter Roeck To: Hardware Monitoring Cc: Jean Delvare , Guenter Roeck , Peter Sulyok Subject: [PATCH] hwmon: (drivetemp) Add usage not describing impact on drive spin-down Date: Tue, 11 Aug 2020 07:57:09 -0700 Message-Id: <20200811145709.55940-1-linux@roeck-us.net> X-Mailer: git-send-email 2.17.1 Sender: linux-hwmon-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org On some drives, reading the drive temperature resets the drive's spin-down timer. If the drive temperature is read too often, affected drives will never spin down. Add this information as usage note to the driver documentation. Reported-by: Peter Sulyok Cc: Peter Sulyok Signed-off-by: Guenter Roeck --- Documentation/hwmon/drivetemp.rst | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/Documentation/hwmon/drivetemp.rst b/Documentation/hwmon/drivetemp.rst index 2d37d049247f..0b1cf2f912c5 100644 --- a/Documentation/hwmon/drivetemp.rst +++ b/Documentation/hwmon/drivetemp.rst @@ -30,6 +30,24 @@ Transport is not supported, the driver uses SMART attributes to read the drive temperature. +Usage Note +---------- + +Reading the drive temperature may reset the spin down timer on some drives. +This has been observed with WD120EFAX drives, but may be seen with other +drives as well. The same behavior is observed if the 'hdtemp' or 'smartd' +tools are used to access the drive. +With the WD120EFAX drive, reading the drive temperature using the drivetemp +driver is still possible _after_ it transitioned to standby mode, and +reading the drive temperature in this mode will not cause the drive to +change its mode (meaning the drive will not spin up). It is unknown if other +drives experience similar behavior. + +A known workaround for WD120EFAX drives is to read the drive temperature at +intervals larger than twice the spin-down time. Otherwise affected drives +will never spin down. + + Sysfs entries -------------