This name can be used to identify the device for special treatment, i.e. only interpolating scrolls coming from mice and not touchpads inside pixel-scroll-precision-mode. * doc/lispref/commands.texi (Command Loop Info): Document new variable `last-event-device'. * etc/NEWS: Announce new variable `last-event-device'. * src/frame.h (struct frame): New field `last_mouse_device'. * src/keyboard.c (read_char): Clear last-event-device. (kbd_buffer_get_event): Set last-event-device to the event's recorded device. (init_keyboard): Clear last-event-device. (syms_of_keyboard): New defvar `last-event-device'. * src/termhooks.h (struct input_event): New field `device'. (EVENT_INIT): Set it to the special value `Qt' by default. * src/xterm.c (x_init_master_valuators): Record the device's name. (x_dnd_begin_drag_and_drop): Only preserve last event device if the mouse ended up in the source frame. (x_note_mouse_movement): New argument `source'. (handle_one_xevent): Set input event sources whenever appropriate. (mark_xterm): Mark device names. * src/xterm.h (struct xi_device_t): New field `name'.