diff options
| -rw-r--r-- | Documentation/video4linux/CARDLIST.bttv | 1 | ||||
| -rw-r--r-- | Documentation/video4linux/v4l2-framework.txt | 11 | ||||
| -rw-r--r-- | drivers/media/video/v4l2-device.c | 15 | ||||
| -rw-r--r-- | include/media/v4l2-device.h | 6 |
4 files changed, 27 insertions, 6 deletions
diff --git a/Documentation/video4linux/CARDLIST.bttv b/Documentation/video4linux/CARDLIST.bttv index f11c583295e9..e17750473e08 100644 --- a/Documentation/video4linux/CARDLIST.bttv +++ b/Documentation/video4linux/CARDLIST.bttv @@ -157,4 +157,3 @@ 156 -> IVCE-8784 [0000:f050,0001:f050,0002:f050,0003:f050] 157 -> Geovision GV-800(S) (master) [800a:763d] 158 -> Geovision GV-800(S) (slave) [800b:763d,800c:763d,800d:763d] -159 -> ProVideo PV183 [1830:1540,1831:1540,1832:1540,1833:1540,1834:1540,1835:1540,1836:1540,1837:1540] diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 4207590b2ac8..a31177390e55 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -105,6 +105,17 @@ You unregister with: Unregistering will also automatically unregister all subdevs from the device. +If you have a hotpluggable device (e.g. a USB device), then when a disconnect +happens the parent device becomes invalid. Since v4l2_device has a pointer to +that parent device it has to be cleared as well to mark that the parent is +gone. To do this call: + + v4l2_device_disconnect(struct v4l2_device *v4l2_dev); + +This does *not* unregister the subdevs, so you still need to call the +v4l2_device_unregister() function for that. If your driver is not hotpluggable, +then there is no need to call v4l2_device_disconnect(). + Sometimes you need to iterate over all devices registered by a specific driver. This is usually the case if multiple device drivers use the same hardware. E.g. the ivtvfb driver is a framebuffer driver that uses the ivtv diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c index b3dcb8454379..94aa485ade52 100644 --- a/drivers/media/video/v4l2-device.c +++ b/drivers/media/video/v4l2-device.c @@ -49,19 +49,26 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) } EXPORT_SYMBOL_GPL(v4l2_device_register); +void v4l2_device_disconnect(struct v4l2_device *v4l2_dev) +{ + if (v4l2_dev->dev) { + dev_set_drvdata(v4l2_dev->dev, NULL); + v4l2_dev->dev = NULL; + } +} +EXPORT_SYMBOL_GPL(v4l2_device_disconnect); + void v4l2_device_unregister(struct v4l2_device *v4l2_dev) { struct v4l2_subdev *sd, *next; if (v4l2_dev == NULL) return; - if (v4l2_dev->dev) - dev_set_drvdata(v4l2_dev->dev, NULL); + v4l2_device_disconnect(v4l2_dev); + /* Unregister subdevs */ list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) v4l2_device_unregister_subdev(sd); - - v4l2_dev->dev = NULL; } EXPORT_SYMBOL_GPL(v4l2_device_unregister); diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h index 3d8e96f6ceb3..0dd3e8e8653e 100644 --- a/include/media/v4l2-device.h +++ b/include/media/v4l2-device.h @@ -53,7 +53,11 @@ struct v4l2_device { dev may be NULL in rare cases (ISA devices). In that case you must fill in the v4l2_dev->name field before calling this function. */ int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev); -/* Set v4l2_dev->dev->driver_data to NULL and unregister all sub-devices */ +/* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects. + Since the parent disappears this ensures that v4l2_dev doesn't have an + invalid parent pointer. */ +void v4l2_device_disconnect(struct v4l2_device *v4l2_dev); +/* Unregister all sub-devices and any other resources related to v4l2_dev. */ void v4l2_device_unregister(struct v4l2_device *v4l2_dev); /* Register a subdev with a v4l2 device. While registered the subdev module |