Occasionally my mouse / keyboard would take extra long to respond to input. If I moved the mouse or pressed a key it would take an extra second to respond the work normally.
If I leave it alone for a period of time the it happens again.
In the dmesg log I see entries like this
dmesg | tail ehci_hcd 0000:00:1d.0: PCI INT A disabled ehci_hcd 0000:00:1d.0: PME# enabled ehci_hcd 0000:00:1d.0: BAR 0: set to [mem 0xd9105800-0xd9105bff] (PCI address [0xd9105800-0xd9105bff]) ehci_hcd 0000:00:1d.0: restoring config space at offset 0xf (was 0x100, writing 0x10b) ehci_hcd 0000:00:1d.0: restoring config space at offset 0x1 (was 0x2900000, writing 0x2900002) ehci_hcd 0000:00:1d.0: PME# disabled ehci_hcd 0000:00:1d.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21 ehci_hcd 0000:00:1d.0: setting latency timer to 64
I found out which device it is but still don't know what is actually causing the issue. I know it has some thing to do with the usb controller.
lspci -n | grep 00:1d.0 00:1d.0 0c03: 8086:3b34 (rev 05) lspci -d 8086:3b34 00:1d.0 USB controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 05)
After a bit of investigation I believe it has some thing to do with power management, power saving or auto suspend of the device.