From 1d29cfa57471a5e4b8a7c2a7433eeba170d3ad92 Mon Sep 17 00:00:00 2001 From: Kuninori Morimoto Date: Tue, 29 May 2012 18:46:06 -0700 Subject: driver core: fixup reversed deferred probe order If driver requests probe deferral, it will be added to deferred_probe_pending_list by driver_deferred_probe_add(), but, it used list_add(). Because of that, deferred probe will be run as reversed order. This patch uses list_add_tail(), and solved this issue. Signed-off-by: Kuninori Morimoto Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/base/dd.c') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 1b1cbb571d3..dcb8a6e4869 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -100,7 +100,7 @@ static void driver_deferred_probe_add(struct device *dev) mutex_lock(&deferred_probe_mutex); if (list_empty(&dev->p->deferred_probe)) { dev_dbg(dev, "Added to deferred list\n"); - list_add(&dev->p->deferred_probe, &deferred_probe_pending_list); + list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list); } mutex_unlock(&deferred_probe_mutex); } -- cgit v1.2.3-70-g09d2 From 0998d0631001288a5974afc0b2a5f568bcdecb4d Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Wed, 23 May 2012 00:09:34 +0200 Subject: device-core: Ensure drvdata = NULL when no driver is bound 1) drvdata is for a driver to store a pointer to driver specific data 2) If no driver is bound, there is no driver specific data associated with the device 3) Thus logically drvdata should be NULL if no driver is bound. But many drivers don't clear drvdata on device_release, or set drvdata early on in probe and leave it set on probe error. Both of which results in a dangling pointer in drvdata. This patch enforce for drvdata to be NULL after device_release or on probe failure. Signed-off-by: Hans de Goede Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/base/dd.c') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 1b1cbb571d3..9a1e9704d78 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -283,6 +283,7 @@ probe_failed: devres_release_all(dev); driver_sysfs_remove(dev); dev->driver = NULL; + dev_set_drvdata(dev, NULL); if (ret == -EPROBE_DEFER) { /* Driver requested deferred probing */ @@ -487,6 +488,7 @@ static void __device_release_driver(struct device *dev) drv->remove(dev); devres_release_all(dev); dev->driver = NULL; + dev_set_drvdata(dev, NULL); klist_remove(&dev->p->knode_driver); if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, -- cgit v1.2.3-70-g09d2 From 8153584e3fdf78753bf653d5f583b6ecb86e5e70 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 5 Jul 2012 14:04:44 +0100 Subject: driver core: Move deferred devices to the end of dpm_list before probing When deferred probe was originally added the idea was that devices which defer their probes would move themselves to the end of dpm_list in order to try to keep the assumptions that we're making about the list being in roughly the order things should be suspended correct. However this hasn't been what's been happening and doing it requires a lot of duplicated code to do the moves. Instead take a simple, brute force solution and have the deferred probe code push devices to the end of dpm_list before it retries the probe. This does mean we lock the dpm_list a bit more often but it's very simple and the code shouldn't be a fast path. We do the move with the deferred mutex dropped since doing things with fewer locks held simultaneously seems like a good idea. This approach was most recently suggested by Grant Likely. Signed-off-by: Mark Brown Acked-by: Rafael J. Wysocki Cc: Grant Likely , Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'drivers/base/dd.c') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 6cd2c6ca9b0..9b0aca47958 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -85,8 +85,20 @@ static void deferred_probe_work_func(struct work_struct *work) * manipulate the deferred list */ mutex_unlock(&deferred_probe_mutex); + + /* + * Force the device to the end of the dpm_list since + * the PM code assumes that the order we add things to + * the list is a good order for suspend but deferred + * probe makes that very unsafe. + */ + device_pm_lock(); + device_pm_move_last(dev); + device_pm_unlock(); + dev_dbg(dev, "Retrying from deferred list\n"); bus_probe_device(dev); + mutex_lock(&deferred_probe_mutex); put_device(dev); -- cgit v1.2.3-70-g09d2 From eed5d2150752bd08b22333d739f3120151773d28 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 12 Jul 2012 11:51:48 +0200 Subject: PM / Runtime: Do not increment device usage counts before probing The pm_runtime_get_noresume() calls before really_probe() and before executing __device_attach() for each driver on the device's bus cause problems to happen if probing fails and if the driver has enabled runtime PM for the device in its .probe() callback. Namely, in that case, if the device has been resumed by the driver after enabling its runtime PM and if it turns out that .probe() should return an error, the driver is supposed to suspend the device and disable its runtime PM before exiting .probe(). However, because the device's runtime PM usage counter was incremented by the core before calling .probe(), the driver's attempt to suspend the device will not succeed and the device will remain in the full-power state after the failing .probe() has returned. To fix this issue, remove the pm_runtime_get_noresume() calls from driver_probe_device() and from device_attach() and replace the corresponding pm_runtime_put_sync() calls with pm_runtime_idle() to preserve the existing behavior (which is to check if the device is idle and to suspend it eventually in that case after probing). Reported-and-tested-by: Kevin Hilman Reviewed-by: Kevin Hilman Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'drivers/base/dd.c') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9b0aca47958..e3bbed8a617 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -369,10 +369,9 @@ 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); - pm_runtime_get_noresume(dev); pm_runtime_barrier(dev); ret = really_probe(dev, drv); - pm_runtime_put_sync(dev); + pm_runtime_idle(dev); return ret; } @@ -419,9 +418,8 @@ int device_attach(struct device *dev) ret = 0; } } else { - pm_runtime_get_noresume(dev); ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); - pm_runtime_put_sync(dev); + pm_runtime_idle(dev); } out_unlock: device_unlock(dev); -- cgit v1.2.3-70-g09d2