[Nut-upsuser] CyberPower usbhid-ups continuously disconnects/reconnects

[Charles Lepple]

On Jun 15, 2011, at 5:40 PM, nut at johnea.net wrote:

> On 06/15/2011 02:24 PM, nut at johnea.net wrote:
>>>
>> -> Does this seems to indicate the conflict of drivers you mentioned?
>
> usbtree data that may indicate driver conflict is the issue:

I think Arnaud was referring to the case where two instances of NUT  
have been installed, and both user-space drivers are trying to re-open  
the device. The "usbhid" driver mentioned below is a kernel driver,  
and unless there is a regression in the kernel driver detach code,  
that shouldn't be an issue.

> The output of usbtree when the device is disconnecting:
> /: Bus 04.Port 1: Dev 1, Class=root_hub, Drv=uhci_hcd/2p, 12M
>    |_ Port 1: Dev 26, If 0, Prod=CP425HG, Class=HID, Drv=usbhid, 1.5M
>
> The output of usbtree once usbhid-ups has succesfully connected:
> /: Bus 04.Port 1: Dev 1, Class=root_hub, Drv=uhci_hcd/2p, 12M
>    |_ Port 1: Dev 27, If 0, Prod=CP425HG, Class=HID, Drv=usbfs, 1.5M
>
> Is there a udev rule that can block the usbhid driver from  
> connecting to the device?

There is a blacklist in the kernel, but I don't think this is the  
issue here. The UPS shouldn't be completely disconnecting, even if two  
drivers are fighting over it. (If that's the case, you just get a  
volley of EBUSY errors between the two drivers.)

Double-check the cabling, because disconnect messages such as the  
following are reported to the kernel by the USB host controller chip:

Jun  8 18:07:28 sensor003 kernel: [  411.500020] usb 3-2: USB  
disconnect, address 19

Is it consistently disconnecting every 20 seconds? That almost sounds  
like some proprietary extension to the HID protocol - the UPS expects  
the computer to send something that only the CyberPower software knows  
to send.