usb/176913: High interrupt load with ehci

[Christian Jurk]

The following reply was made to PR usb/176913; it has been noted by GNATS.

From: Christian Jurk <commx at commx.ws>
To: bug-followup at FreeBSD.org
Cc:  
Subject: Re: usb/176913: High interrupt load with ehci
Date: Wed, 13 Mar 2013 18:08:28 +0100

 Not sure if that problem is directly a USB problem, might be better to =
 move it into a more appropriate category if possible.
 
 What I did recently: Did a reboot (by using command `reboot') - the =
 system did not reboot on its own. All I got on the screen was:
 
 Syncing disks, vnodes remaining=859 2 2 2 1 1 1 0 0 done
 All buffers synced.
 Uptime: 14h58m19s
 usbus0: Controller shutdown
 uhub0: at usbus0, port 1, addr 1 (disconnected)
 ugen0.2: <vendor 0x8087> at usbus0 (disconnected)
 uhub4: at uhub0, port 1, addr 2 (disconnected)
 usbus0: Controller shutdown complete
 re0: link state changed to DOWN
 re0: link state changed to UP
 usbus1: Controller shutdown
 
 After waiting 30 minutes, I decided to power cycle the machine. After =
 reboot, the Zpool on the USB disk was not be able to mount because of a =
 missing label (the error message referred to =
 http://illumos.org/msg/ZFS-8000-5E). Thus, I had to destroy the zpool =
 and re-created it. I've copied lots of files to a ZFS volume on top of =
 the zpool and tried to reboot the machine. Got the same problem again. =
 Seeing usbub1: Controller shutdown but nothing happens. I see a relation =
 between the high interrupt rate and the USB device for some reason. =
 `zpool iostat 1` shows me that there are no read or write operations on =
 the device.=