Hi, when testing hidraw's hid-example.c (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/samples/hidraw/hid-example.c) with a Bluetooth HID device, I noticed that the write() call always returns 0 on success, even though the entire buffer has been written and received by the device. Following the chain of calls triggered by the call to write(), I identified hidp_send_message in /net/bluetooth/hidp/core.c:98 (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/bluetooth/hidp/core.c#n98) as the plausible origin of the return value. This function always returns 0 on success, regardless of the value of its parameter size. Could you confirm whether this function is really the one used to handle writes to Bluetooth HID devices? If so, is it intended behavior to have write() return the number of bytes written for USB HID devices, but not for Bluetooth HID devices?
