udev has this nice feature of creating "dead" /dev/<node> device-nodes if it finds a devnode:<node> modalias. Once the node is accessed, the kernel automatically loads the module that provides the node. However, this requires udev to know the major:minor code to use for the node. This feature was introduced by:
commit 578454ff7eab61d13a26b568f99a89a2c9edc881 Author: Kay Sievers <[email protected]> Date: Thu May 20 18:07:20 2010 +0200 driver core: add devname module aliases to allow module on-demand auto-loading However, uhid uses dynamic minor numbers so this doesn't actually work. We need to load uhid to know which minor it's going to use. Hence, allocate a static minor (just like uinput does) and we're good to go. Reported-by: Tom Gundersen <[email protected]> Signed-off-by: David Herrmann <[email protected]> --- drivers/hid/uhid.c | 3 ++- include/linux/miscdevice.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 5bf2fb7..93b00d7 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -615,7 +615,7 @@ static const struct file_operations uhid_fops = { static struct miscdevice uhid_misc = { .fops = &uhid_fops, - .minor = MISC_DYNAMIC_MINOR, + .minor = UHID_MINOR, .name = UHID_NAME, }; @@ -634,4 +634,5 @@ module_exit(uhid_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("David Herrmann <[email protected]>"); MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem"); +MODULE_ALIAS_MISCDEV(UHID_MINOR); MODULE_ALIAS("devname:" UHID_NAME); diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h index 09c2300..cb35835 100644 --- a/include/linux/miscdevice.h +++ b/include/linux/miscdevice.h @@ -45,6 +45,7 @@ #define MAPPER_CTRL_MINOR 236 #define LOOP_CTRL_MINOR 237 #define VHOST_NET_MINOR 238 +#define UHID_MINOR 239 #define MISC_DYNAMIC_MINOR 255 struct device; -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
