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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.

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up vote 1 down vote accepted

After quite a bit of googling I remembered I has installed powernap.

sudo powernap-action -l

[disabled] 01cpu_online         - sh: 1: /etc/pm/power.d/01cpu_online: Permission denied  
[enabled]  00flag               -  
[disabled] usb                  - sh: 1: /etc/pm/power.d/usb: Permission denied  
[disabled] video                - sh: 1: /etc/pm/power.d/video: Permission denied  
[disabled] eth_speed            - sh: 1: /etc/pm/power.d/eth_speed: Permission denied  
[enabled]  usb_autosuspend      - Auto suspend USB bus to save power.  
[enabled]  cpu_frequency        - Lowers the CPU frequency, changing the scaling governor from ondemand to powersave.  
[disabled] kms_powermode        - sh: 1: /etc/pm/power.d/kms_powermode: Permission denied  

One of the options I had enabled was

[enabled]  usb_autosuspend      - Auto suspend USB bus to save power.

So I fixed the issue by disabling usb_autosuspend.

sudo powernap-action --disable usb_autosuspend

So Now

[disabled] usb_autosuspend      - sh: 1: /etc/pm/power.d/usb_autosuspend: Permission denied
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