Hi Aniroop, On Thu, Jan 09, 2014 at 10:27:56AM +0530, Aniroop Mathur wrote: > This patch allows user(driver) to set sysfs node name of input > devices. To set sysfs node name, user(driver) just needs to set > node_name_unique variable. If node_name_unique is not set, default > name is given(as before). So, this patch is completely > backward-compatible. > > Sysfs Input node name format is: input_<name> > Sysfs Event node name format is: event_<name> > > This "name" is given by user and automatically, prefix(input and > event) is added by input core. > > This name must be unique among all input devices and driver(user) has > the responsibility to ensure it. If same name is used again for other > input device, registration of that input device will fail because two > input devices cannot have same name. > > Advantages of this patch are: > > 1. Reduces Booting Time of HAL/Upper-Layer because now HAL or > Upper-Layer do not need to search input/event number corresponding to > each input device in /dev/input/... This searching in /dev/input/ was > taking too much time. (Especially in mobile devices, where there are > many input devices (many sensors, touchscreen, etc), it reduces a lot > of booting time) I am sorry, how much time does it take to scan a directory of what, 20 devices? If it such a factor have udev create nodes that are easier for you to locate, similarly how we already create nodes by-id and by-path. For example you can encode major:minor in device name. > > 2. Improves Readabilty of input and event sysfs node paths because > names are used instead of numbers. I do not see why it is that important. If one wants overview /proc/bus/input/devices gives nice picture. > > 3. Removes Input Devices Dependency. If one input device probe fails, > other input devices still work. Before this patch, if one input > device probe fails before input_register_device, then input number of > other input devices changes and due to this permission settings are > disturbed and hence HAL or upper layer cannot open the required sysfs > node because permission denied error comes. I have only one suggestion here: fix your userspace so that does not depend on device initialization ordering. IOW I am totally unconvinced that this facility is needed. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
