short form: is there some reason that the usbhid "quirks" parameter is not by default compiled to be writable in case you wanted to adjust those values on a running system? long form: i have a USB device that, sadly, is automatically claimed by the usbhid driver upon insertion, and i want to prevent that so it behaves as a regular USB device. from what i've read, the solution is to, at boot time, add the kernel command line parameter: usbhid.quirks=0x2123:0x1010:0x04 that's fine if i want to reboot so that that takes effect, but it would of course be convenient if i could add that info to /sys/module/usbhid/parameters/quirks at run-time. currently, on my fedora 22 system: $ cat /sys/module/usbhid/parameters/quirks (null),(null),(null),(null) $ with permissions: $ ls -l /sys/module/usbhid/parameters/quirks -r--r--r--. 1 root root 4096 Nov 12 02:41 /sys/module/usbhid/parameters/quirks $ and i can see in drivers/hid/usbhid/hid-core.c the fact that that array is defined as non-writable: /* Quirks specified at module load time */ static char *quirks_param[MAX_USBHID_BOOT_QUIRKS]; module_param_array_named(quirks, quirks_param, charp, NULL, 0444); MODULE_PARM_DESC(quirks, "Add/modify USB HID quirks by specifying " " quirks=vendorID:productID:quirks" " where vendorID, productID, and quirks are all in" " 0x-prefixed hex"); so the obvious(?) question is, is there some reason that that parameter is defined as read-only rather than, say, writable by root? would it not be useful to be able to modify that parameter at run-time? or is there something about that parameter for which that would be a really bad idea? rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================