[Nut-upsuser] blazer_usb and USBDEVFS_CONTROL failed

Charles Lepple clepple at gmail.com
Tue Nov 26 01:16:27 UTC 2013

On Nov 25, 2013, at 4:56 PM, Fabio Cecamore wrote:

> Hi all,
> after a change of UPS (to Atlantis Host Power 851) I began to use the new driver blazer_usb and compared to old one (blazer used with serial connection) I noted more CPU use and errors in dmesg:
> [...]
> [256712.584370] usb 4-5: usbfs: USBDEVFS_CONTROL failed cmd blazer_usb rqt 33 rq 9 len 8 ret -110

"ret -110" is a timeout, I believe.

> Obviously the usb ports work good, I think is a bug in the driver or something like..

Could be a cable problem, too.

What version of NUT? We increased the timeout in 2.7.1.

Also, devices that talk to blazer_usb are basically serial UPSes with a USB-to-serial converter. The increased CPU usage is not surprising, since the host now has to poll the USB-to-serial converter (rather than the UART interrupting the CPU when data is ready). Do you have any profiling data to show how much more CPU time is being used?

Charles Lepple
clepple at gmail

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