Messages in this thread Patch in this message | | | Subject | Re: [linux-usb-devel] Re: usb sysfs intf files no longer created when probe fails | From | Stelian Pop <> | Date | Wed, 22 Jun 2005 17:53:28 +0200 |
| |
Le mercredi 22 juin 2005 à 11:41 -0400, Alan Stern a écrit :
> This is a curious aspect of the driver model core. Should failure of a > driver to bind be considered serious enough to cause device_add to fail? > The current answer is Yes unless the driver's probe routine returns > -ENODEV or -ENXIO, in which case the failure is not considered serious.
Indeed. I've also tracked my problem down to the hid core which returns -EIO when it fails to drive an unknown HID device, instead of a more logical -ENODEV (this is not a failure to init a known device, but rather the impossibility to init an unknown device).
The patch below solves the problem for me:
Index: linux-2.6-trunk.git/drivers/usb/input/hid-core.c =================================================================== --- linux-2.6-trunk.git.orig/drivers/usb/input/hid-core.c 2005-06-22 10:33:23.000000000 +0200 +++ linux-2.6-trunk.git/drivers/usb/input/hid-core.c 2005-06-22 17:43:10.000000000 +0200 @@ -1784,7 +1784,7 @@ if (!hid->claimed) { printk ("HID device not claimed by input or hiddev\n"); hid_disconnect(intf); - return -EIO; + return -ENODEV; } printk(KERN_INFO);
> IMO this is a perverse way of doing things. The existence of a device has > nothing to do with what driver is bound to it. Either the device exists > or it doesn't -- and if it exists, failure to bind a driver shouldn't > prevent adding the device into sysfs. Right now, however, it does.
I agree, presence in /sys/devices shouldn't be related to the existence or success/failure of a driver. The link between /sys/class towards /sys/devices is already saying this.
Stelian. -- Stelian Pop <stelian@popies.net>
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |