diff options
| author | Ben Hutchings <ben.hutchings@codethink.co.uk> | 2016-08-16 14:34:18 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-11-10 17:22:23 +0100 |
| commit | 6751667a29d6fd64afb9ce30567ad616b68ed789 (patch) | |
| tree | 128403d3fb1187222f340b3676310ef376d17699 | |
| parent | baa8809f60971d10220dfe79248f54b2b265f003 (diff) | |
driver core: Add deferred_probe attribute to devices in sysfs
It is sometimes useful to know that a device is on the deferred probe
list rather than, say, not having a driver available. Expose this
information to user-space.
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-deferred_probe | 12 | ||||
| -rw-r--r-- | drivers/base/base.h | 2 | ||||
| -rw-r--r-- | drivers/base/core.c | 7 | ||||
| -rw-r--r-- | drivers/base/dd.c | 13 |
4 files changed, 34 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-deferred_probe b/Documentation/ABI/testing/sysfs-devices-deferred_probe new file mode 100644 index 000000000000..58553d7a321f --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-deferred_probe @@ -0,0 +1,12 @@ +What: /sys/devices/.../deferred_probe +Date: August 2016 +Contact: Ben Hutchings <ben.hutchings@codethink.co.uk> +Description: + The /sys/devices/.../deferred_probe attribute is + present for all devices. If a driver detects during + probing a device that a related device is not yet + ready, it may defer probing of the first device. The + kernel will retry probing the first device after any + other device is successfully probed. This attribute + reads as 1 if probing of this device is currently + deferred, or 0 otherwise. diff --git a/drivers/base/base.h b/drivers/base/base.h index e19b1008e5fb..ada9dce34e6d 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -141,6 +141,8 @@ extern void device_unblock_probing(void); extern struct kset *devices_kset; extern void devices_kset_move_last(struct device *dev); +extern struct device_attribute dev_attr_deferred_probe; + #if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS) extern void module_add_driver(struct module *mod, struct device_driver *drv); extern void module_remove_driver(struct device_driver *drv); diff --git a/drivers/base/core.c b/drivers/base/core.c index d0c9df5cdd9e..b8b2f6105476 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1060,8 +1060,14 @@ static int device_add_attrs(struct device *dev) goto err_remove_dev_groups; } + error = device_create_file(dev, &dev_attr_deferred_probe); + if (error) + goto err_remove_online; + return 0; + err_remove_online: + device_remove_file(dev, &dev_attr_online); err_remove_dev_groups: device_remove_groups(dev, dev->groups); err_remove_type_groups: @@ -1079,6 +1085,7 @@ static void device_remove_attrs(struct device *dev) struct class *class = dev->class; const struct device_type *type = dev->type; + device_remove_file(dev, &dev_attr_deferred_probe); device_remove_file(dev, &dev_attr_online); device_remove_groups(dev, dev->groups); diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 43be1cc751a4..a48cf444eca5 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -53,6 +53,19 @@ static LIST_HEAD(deferred_probe_pending_list); static LIST_HEAD(deferred_probe_active_list); static atomic_t deferred_trigger_count = ATOMIC_INIT(0); +static ssize_t deferred_probe_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + bool value; + + mutex_lock(&deferred_probe_mutex); + value = !list_empty(&dev->p->deferred_probe); + mutex_unlock(&deferred_probe_mutex); + + return sprintf(buf, "%d\n", value); +} +DEVICE_ATTR_RO(deferred_probe); + /* * In some cases, like suspend to RAM or hibernation, It might be reasonable * to prohibit probing of devices as it could be unsafe. |