usb/156596: [ehci] Extremely high interrupt rate on ehci/uhci IRQ16 80% cpu utilization on CPU0

[Hans Petter Selasky]

The following reply was made to PR usb/156596; it has been noted by GNATS.

From: Hans Petter Selasky <hselasky at c2i.net>
To: bug-followup at freebsd.org,
 daynejordan at gmail.com
Cc:  
Subject: usb/156596: [ehci] Extremely high interrupt rate on ehci/uhci IRQ16 80% cpu utilization on CPU0
Date: Sun, 24 Apr 2011 10:26:52 +0200

 Hi,
 
 Compile a kernel with:
 
 options USB_DEBUG
 
 Then enable after boot:
 
 sysctl hw.usb.ehci.debug=15 ; sleep 1; sysctl hw.usb.ehci.debug=0
 
 sysctl hw.usb.uhci.debug=15 ; sleep 1; sysctl hw.usb.uhci.debug=0
 
 
 The high interrupt rate might be caused by a non-cleared IRQ.
 
 Else it is an ACPI issue.
 
 --HPS