Hello, Right now the hid-logitech-dj driver will export one node for each connected device, even when the device is not connected. That causes some trouble because in userspace we don't have have any way to know if the device is connected or not, so when we try to communicate, if the device is disconnected it will fail. The reason we do this is because otherwise we would loose the first packets when the device is turned on by key press. When a device is turned on we would have to create the device node, and the packets received while we are creating the device node would be lost. This could solved by buffering those packets, but that is a bad solution as it would mess up the timings. At the moment the created node includes both normal HID and vendor usages. To solve this problem, I propose that instead of creating a single device node that contains all usages, we create one for normal HID, which would exist all the time, and one for the vendor usage, which would go away when the device disconnects. This slight behavior change will affect userspace. Two hidraw nodes would be created instead of one. We need to make sure the current userspace stacks interfacing with this would be able to properly handle such changes. What do you think of this approach? Anyone has a better idea? If you are CCed you might be maintaining one of the affected userspace stacks, if so, please let me know your project is able to handle this. If not, I can help you adapt to the new behavior. Thank you, Filipe Laíns
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