Commit 19872d20 authored Sep 09, 2013 by David Herrmann Committed by Jiri Kosina Sep 26, 2013

HID: uhid: allocate static minor



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 578454ff
  Author: Kay Sievers <kay.sievers@vrfy.org>
  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@jklm.no>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

parent 84fca9f3

drivers/hid/uhid.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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@gmail.com>");
		MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
		MODULE_ALIAS_MISCDEV(UHID_MINOR);
		MODULE_ALIAS("devname:" UHID_NAME);

include/linux/miscdevice.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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;