From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755370AbbGFMWx (ORCPT ); Mon, 6 Jul 2015 08:22:53 -0400 Received: from mga01.intel.com ([192.55.52.88]:2068 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754965AbbGFMWq (ORCPT ); Mon, 6 Jul 2015 08:22:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,414,1432623600"; d="scan'208";a="756823963" From: Andy Shevchenko To: linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, Greg Kroah-Hartman , Vinod Koul , Lee Jones , Andrew Morton , Mika Westerberg , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Heikki Krogerus , Jarkko Nikula , "Wysocki, Rafael J" , mturquette@baylibre.com Cc: Andy Shevchenko Subject: [PATCH v5 3/8] Driver core: wakeup the parent device before trying probe Date: Mon, 6 Jul 2015 15:22:09 +0300 Message-Id: <1436185334-34275-4-git-send-email-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436185334-34275-1-git-send-email-andriy.shevchenko@linux.intel.com> References: <1436185334-34275-1-git-send-email-andriy.shevchenko@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Rafael J. Wysocki" If the parent is still suspended when driver probe is attempted, the result may be failure. For example, if the parent is a PCI MFD device that has been suspended when we try to probe our device, any register reads will return 0xffffffff. To fix the problem, making sure the parent is always awake before attempting driver probe. Signed-off-by: Heikki Krogerus Signed-off-by: Rafael J. Wysocki Signed-off-by: Andy Shevchenko --- drivers/base/dd.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index a638bbb..2d6df1d 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -399,6 +399,8 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe); * * This function must be called with @dev lock held. When called for a * USB interface, @dev->parent lock must be held as well. + * + * If the device has a parent, runtime-resume the parent before driver probing. */ int driver_probe_device(struct device_driver *drv, struct device *dev) { @@ -410,10 +412,16 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); + if (dev->parent) + pm_runtime_get_sync(dev->parent); + pm_runtime_barrier(dev); ret = really_probe(dev, drv); pm_request_idle(dev); + if (dev->parent) + pm_runtime_put(dev->parent); + return ret; } @@ -507,11 +515,17 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) device_lock(dev); + if (dev->parent) + pm_runtime_get_sync(dev->parent); + bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver); dev_dbg(dev, "async probe completed\n"); pm_request_idle(dev); + if (dev->parent) + pm_runtime_put(dev->parent); + device_unlock(dev); put_device(dev); @@ -541,6 +555,9 @@ static int __device_attach(struct device *dev, bool allow_async) .want_async = false, }; + if (dev->parent) + pm_runtime_get_sync(dev->parent); + ret = bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver); if (!ret && allow_async && data.have_async) { @@ -557,6 +574,9 @@ static int __device_attach(struct device *dev, bool allow_async) } else { pm_request_idle(dev); } + + if (dev->parent) + pm_runtime_put(dev->parent); } out_unlock: device_unlock(dev); -- 2.1.4