From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0A79C200A6 for ; Fri, 21 Jul 2023 19:03:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80C4FC433C8; Fri, 21 Jul 2023 19:03:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689966210; bh=4xh1NKZZpNJKBfSAkezYozJCd3/80c5DgLCZQn58KcI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qvTaZlzUrt+TNKKEpYlSLBGqSCci5Qn6UqwQrmKEAySy0RBAzqgTNbaD4QOD4HtgI Mr7EArEh1A+oW/s1bUfxNkxvHTZBuAQKP6ftNyrEVO1/3lyT04ZJGhbFildjCyV83m T6lVvSL0f8TiM4pdG/rpoSB9jiqxTm7usKoPEue4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stefan Wahren , Krzysztof Kozlowski , Sasha Levin Subject: [PATCH 5.15 264/532] w1: w1_therm: fix locking behavior in convert_t Date: Fri, 21 Jul 2023 18:02:48 +0200 Message-ID: <20230721160628.671098504@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160614.695323302@linuxfoundation.org> References: <20230721160614.695323302@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Stefan Wahren [ Upstream commit dca5480ab7b77a889088ab7cac81934604510ac7 ] The commit 67b392f7b8ed ("w1_therm: optimizing temperature read timings") accidentially inverted the logic for lock handling of the bus mutex. Before: pullup -> release lock before sleep no pullup -> release lock after sleep After: pullup -> release lock after sleep no pullup -> release lock before sleep This cause spurious measurements of 85 degree (powerup value) on the Tarragon board with connected 1-w temperature sensor (w1_therm.w1_strong_pull=0). In the meantime a new feature for polling the conversion completion has been integrated in these branches with commit 021da53e65fd ("w1: w1_therm: Add sysfs entries to control conversion time and driver features"). But this feature isn't available for parasite power mode, so handle this separately. Link: https://lore.kernel.org/regressions/2023042645-attentive-amends-7b0b@gregkh/T/ Fixes: 67b392f7b8ed ("w1_therm: optimizing temperature read timings") Signed-off-by: Stefan Wahren Link: https://lore.kernel.org/r/20230427112152.12313-1-stefan.wahren@i2se.com Signed-off-by: Krzysztof Kozlowski Signed-off-by: Sasha Levin --- drivers/w1/slaves/w1_therm.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c index 9cbeeb4923ecf..67d1cfbbb5f7f 100644 --- a/drivers/w1/slaves/w1_therm.c +++ b/drivers/w1/slaves/w1_therm.c @@ -1093,29 +1093,26 @@ static int convert_t(struct w1_slave *sl, struct therm_info *info) w1_write_8(dev_master, W1_CONVERT_TEMP); - if (strong_pullup) { /*some device need pullup */ + if (SLAVE_FEATURES(sl) & W1_THERM_POLL_COMPLETION) { + ret = w1_poll_completion(dev_master, W1_POLL_CONVERT_TEMP); + if (ret) { + dev_dbg(&sl->dev, "%s: Timeout\n", __func__); + goto mt_unlock; + } + mutex_unlock(&dev_master->bus_mutex); + } else if (!strong_pullup) { /*no device need pullup */ sleep_rem = msleep_interruptible(t_conv); if (sleep_rem != 0) { ret = -EINTR; goto mt_unlock; } mutex_unlock(&dev_master->bus_mutex); - } else { /*no device need pullup */ - if (SLAVE_FEATURES(sl) & W1_THERM_POLL_COMPLETION) { - ret = w1_poll_completion(dev_master, W1_POLL_CONVERT_TEMP); - if (ret) { - dev_dbg(&sl->dev, "%s: Timeout\n", __func__); - goto mt_unlock; - } - mutex_unlock(&dev_master->bus_mutex); - } else { - /* Fixed delay */ - mutex_unlock(&dev_master->bus_mutex); - sleep_rem = msleep_interruptible(t_conv); - if (sleep_rem != 0) { - ret = -EINTR; - goto dec_refcnt; - } + } else { /*some device need pullup */ + mutex_unlock(&dev_master->bus_mutex); + sleep_rem = msleep_interruptible(t_conv); + if (sleep_rem != 0) { + ret = -EINTR; + goto dec_refcnt; } } ret = read_scratchpad(sl, info); -- 2.39.2