>> I'm writing a kernel module, but probe() is never called since usbhid
>> claims the usb device as soon as the device is plugged in.
>
> What type of module for what type of device? And why do you want to
> override the hid driver from binding to it?
>
> thanks,
>
> greg k-h
I'm just learning about device drivers, so I'm writing a dummy usb
device driver. I've pasted the code here (I hope the formatting is
correct):
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>
static int mmod_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
pr_debug("mmod: probe is called");
/* return -ENODEV if we don't want to claim the device */
return 0;
}
static void mmod_disc(struct usb_interface *intf)
{
pr_debug("mmod: disconnected");
}
static const struct usb_device_id mmod_id[] = {
{.match_flags = USB_DEVICE_ID_MATCH_INT_PROTOCOL,
.bInterfaceClass = 0x01
},
{}
};
/* export the id to userspace */
MODULE_DEVICE_TABLE(usb, mmod_id);
static struct usb_driver mmod_driver = {
.name = "mmod_driver",
.id_table = mmod_id,
.probe = mmod_probe,
.disconnect = mmod_disc
};
static int __init init_task05(void)
{
pr_debug("mmod loaded");
usb_register(&mmod_driver);
return 0;
}
static void __exit exit_mymod(void)
{
pr_debug("mmod unloaded");
usb_deregister(&mmod_driver);
}
module_init(init_mmod);
module_exit(exit_mmod);
MODULE_LICENSE("GPL");
I can load and unload the module and I can see the messages being
printed. I can also see usbcore registering the new driver in dmesg,
but when I plug any usb keyboard (which I have registered in id
table), the probe never gets called. Instead, I see usbhid taking over
and initializing the device in dmesg. And as far as intention goes,
this is just for fun.
I have thought about editing hid-core.c and adding usb quirks there
and recompile the kernel, but that seems a bit drastic. I thought
maybe there's a better way to do it.
Thanks a lot,
--
Armin Moradi
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