Re: [PATCH] HID: uhid: allocate static minor
From: Tom Gundersen <hidden>
Date: 2013-09-09 16:52:21
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On Mon, Sep 9, 2013 at 6:33 PM, David Herrmann [off-list ref] wrote:
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 [off-list ref]
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 <redacted>Thanks, this works (I only tested the creation of the device node, not the actual module loading).
quoted hunk ↗ jump to hunk
Signed-off-by: David Herrmann <redacted> --- 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@gmail.com>"); 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