This is simultaneously caused by the kernel input subsystem not using the new driver core, and the changes to udev to obsolete the /etc/dev.d and /etc/hotplug.d directories. With the new driver core the driver has an opportunity to add environment to the uevent[0] generated along with the sysfs information before the event is sent to userspace via the netlink socket and, for backwards compatibility, the /proc/sys/kernel/hotplug interface. However the input subsystem isn't yet doing this, so the sysfs-generated event doesn't carry any of the PRODUCT, EV, KEY, etc. environment variables describing the input device. Instead the input subsystem has its own function to generate the environment for a call to the /proc/sys/kernel/hotplug helper. This is done in drivers/input.c input_call_hotplug(). Because this isn't related to the sysfs event, there's no way for it to include the DEVPATH variable that points to the path in the sysfs filesystem. There are patches starting to float around now to update the kernel to use the new driver core; at this point udev will be able to drop /proc/sys/kernel/hotplug compatibility completely as all events will come from the netlink socket and be well-formed. udev *used* to handle this; when it received an event without the required variables it would skip any udev.rules processing and just run the old /etc/hotplug.d/ scripts. udev-0.059 dropped direct support for these scripts, and instead included a "udev_run_hotplugd" helper that distributions could chose to ship alongside and add a udev.rules entry to run it. This also meant that support for the "malformed" uevents was dropped at the same time, as there's no way to perform udev.rules checking with them. The right solution, long-term, is for the kernel to use the new driver core for the input subsystem. This will mean all sorts of hacks will go away, and bring us one step closer to world peace and stuff. The short term solution we've adopted in Ubuntu is the attached patch that handles input subsystem events that are missing a devpath by directly execing udev_run_hotplugd and letting that deal with it. Scott [0] the new name for what used to be hotplug events. -- Scott James Remnant scott@ubuntu.com
diff -ruNp udev-060.orig/udev.c udev-060/udev.c
--- udev-060.orig/udev.c 2005-09-23 23:08:25.374883000 +0100
+++ udev-060/udev.c 2005-09-23 23:22:45.034195864 +0100
@@ -114,11 +114,25 @@ int main(int argc, char *argv[], char *e
if (!subsystem && argc == 2)
subsystem = argv[1];
- if (!action || !subsystem || !devpath) {
- err("action, subsystem or devpath missing");
+ if (!action || !subsystem) {
+ err("action or subsystem missing");
goto exit;
}
+ if (!devpath) {
+ if (!strcmp(subsystem, "input")) {
+ dbg("input event without devpath");
+ logging_close();
+
+ execv("/sbin/udev_run_hotplugd", argv);
+ err("exec of child failed");
+ _exit(1);
+ } else {
+ err("devpath missing");
+ goto exit;
+ }
+ }
+
/* export log_priority , as called programs may want to do the same as udev */
if (udev_log_priority) {
char priority[32];
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