From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753901AbeFDHFD (ORCPT ); Mon, 4 Jun 2018 03:05:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:57106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753886AbeFDHFA (ORCPT ); Mon, 4 Jun 2018 03:05:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bastien Nocera , Srinivas Pandruvada , Hans de Goede , Stable@vger.kernel.org, Jonathan Cameron Subject: [PATCH 4.16 26/47] iio: hid-sensor-trigger: Fix sometimes not powering up the sensor after resume Date: Mon, 4 Jun 2018 08:58:38 +0200 Message-Id: <20180604065550.580372107@linuxfoundation.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180604065549.468488465@linuxfoundation.org> References: <20180604065549.468488465@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hans de Goede commit 6f92253024d9d947a4f454654840ce479e251376 upstream. hid_sensor_set_power_work() powers the sensors back up after a resume based on the user_requested_state atomic_t. But hid_sensor_power_state() treats this as a boolean flag, leading to the following problematic scenario: 1) Some app starts using the iio-sensor in buffered / triggered mode, hid_sensor_data_rdy_trigger_set_state(true) gets called, setting user_requested_state to 1. 2) Something directly accesses a _raw value through sysfs, leading to a call to hid_sensor_power_state(true) followed by hid_sensor_power_state(false) call, this sets user_requested_state to 1 followed by setting it to 0. 3) Suspend/resume the machine, hid_sensor_set_power_work() now does NOT power the sensor back up because user_requested_state (wrongly) is 0. Which stops the app using the sensor in buffered mode from receiving any new values. This commit changes user_requested_state to a counter tracking how many times hid_sensor_power_state(true) was called instead, fixing this. Cc: Bastien Nocera Cc: Srinivas Pandruvada Signed-off-by: Hans de Goede Acked-by: Srinivas Pandruvada Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/common/hid-sensors/hid-sensor-trigger.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/iio/common/hid-sensors/hid-sensor-trigger.c +++ b/drivers/iio/common/hid-sensors/hid-sensor-trigger.c @@ -178,14 +178,14 @@ int hid_sensor_power_state(struct hid_se #ifdef CONFIG_PM int ret; - atomic_set(&st->user_requested_state, state); - if (atomic_add_unless(&st->runtime_pm_enable, 1, 1)) pm_runtime_enable(&st->pdev->dev); - if (state) + if (state) { + atomic_inc(&st->user_requested_state); ret = pm_runtime_get_sync(&st->pdev->dev); - else { + } else { + atomic_dec(&st->user_requested_state); pm_runtime_mark_last_busy(&st->pdev->dev); pm_runtime_use_autosuspend(&st->pdev->dev); ret = pm_runtime_put_autosuspend(&st->pdev->dev);