I have upgraded kernel from gentoo-sources 3.17.7 to 3.17.8-r1 and since then after boot mouse Logitech G9X doesn't work. If I'm lucky, I have to pull it off andf than back. Then sometimes it starts working. I get this in /var/log/messages: Feb 9 12:09:51 triarius kernel: usb 2-1.2: USB disconnect, device number 4 Feb 9 12:09:58 triarius kernel: usb 2-1.2: new full-speed USB device number 6 using ehci-pci Feb 9 12:09:58 triarius kernel: usb 2-1.2: New USB device found, idVendor=046d, idProduct=c066 Feb 9 12:09:58 triarius kernel: usb 2-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Feb 9 12:09:58 triarius kernel: usb 2-1.2: Product: G9x Laser Mouse Feb 9 12:09:58 triarius kernel: usb 2-1.2: Manufacturer: Logitech Feb 9 12:09:58 triarius kernel: usb 2-1.2: SerialNumber: 085E959EC40018 Feb 9 12:09:58 triarius kernel: input: Logitech G9x Laser Mouse as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/0003:046D:C066.0005/input/input11 Feb 9 12:09:58 triarius kernel: hid-generic 0003:046D:C066.0005: input,hidraw0: USB HID v1.11 Mouse [Logitech G9x Laser Mouse] on usb-0000:00:1d.0-1.2/input0 Feb 9 12:09:58 triarius kernel: input: Logitech G9x Laser Mouse as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.1/0003:046D:C066.0006/input/input12 Feb 9 12:09:58 triarius kernel: input: failed to attach handler kbd to device input12, error: -16 Feb 9 12:09:58 triarius kernel: sysrq: Failed to open input device, error -16 Feb 9 12:09:58 triarius mtp-probe: checking bus 2, device 6: "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2" Feb 9 12:09:58 triarius mtp-probe: bus: 2, device: 6 was not an MTP device Feb 9 12:09:58 triarius kernel: input: failed to attach handler sysrq to device input12, error: -16 Feb 9 12:09:58 triarius kernel: hid-generic 0003:046D:C066.0006: input,hiddev0,hidraw1: USB HID v1.11 Keyboard [Logitech G9x Laser Mouse] on usb-0000:00:1d.0-1.2/input1 Then this message pops out, mouse works. When there are no error: -16 in message, it does not. Its LED lights are on all the time. I tested in BIOS, Windows 7 and Ubuntu 14.04 and Gentoo on kernel 3.17.7 where this mouse works. Gentoo kernel 3.17.8 and 3.18.6 have this issue. I also tried 3.18.6 vanilla where I suffer from the same issue. So it looks like regression introduced with 3.17.8. Reproducible: Always Steps to Reproduce: 1. Have mouse Logitech G9X in USB 2. Boot kernel 3.17.8 and older 3. Mouse doesn't move although its LEDs are on.
Are you plugging it into a hub? Can you try different usb ports to see if that helps? Would you consider doing a git bisect to figure out the problem commit between the first non-working kernel and the last working kernel?