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 <kay.sievers@xxxxxxxx>
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 <teg@xxxxxxx>
Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
---
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 <dh.herrmann@xxxxxxxxx>");
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
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