Partially I solved the problem with Cougar 500K. The problem lies in the fact that this keyboard has three interfaces (in terms of USB), for the first two (keyboard and mouse) the kernel attaches the input driver (from dmesg):
0003:060B:500A.0001: input,hidraw0: USB HID v1.11 Keyboard [Cougar500k Cougar500k Gaming Keyboard] on usb-0000:00:06.0-1/input0 ----> input: Cougar500k Cougar500k Gaming Keyboard as /devices/pci0000:00/0000:00:06.0/usb2/2-1/2-1:1.0/0003:060B:500A.0001/input/input6 0003:060B:500A.0002: input,hiddev0,hidraw2: USB HID v1.11 Mouse [Cougar500k Cougar500k Gaming Keyboard] on usb-0000:00:06.0-1/input1 ----> input: Cougar500k Cougar500k Gaming Keyboard as /devices/pci0000:00/0000:00:06.0/usb2/2-1/2-1:1.1/0003:060B:500A.0002/input/input7 and for the third it does not (from dmesg): 0003:060B:500A.0003: hiddev0,hidraw1: USB HID v1.11 Device [Cougar500k Cougar500k Gaming Keyboard] on usb-0000:00:06.0-1/input2 ----> !!!!! no input driver attached !!!!! Problem arise due to the lack of an input driver for the third interface. When you press any additional extended key, the microcontroller of the keyboard generates the USB packets for transmission through the third interface to kernel. And the keyboard microcontroller will stop his work until the kernel driver process this USB packets. I solved this problem ugly (due insufficient knowledge in writing drivers for Linux and HID devices). I connect the simplest input driver to the third interface which reads USB packets without processing any data in packet. As a result, the main keys work, but additional keys not. But at least the keyboard no longer freezes when I press additional keys. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1511511 Title: USB keyboard stops working after pressing extended key To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1511511/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
