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

[Andrew Fremantle]

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

From: Andrew Fremantle <andrew at skyhawk.ca>
To: bug-followup at FreeBSD.org, daynejordan at gmail.com
Cc:  
Subject: Re: usb/156596: [ehci] Extremely high interrupt rate on ehci/uhci
 IRQ16 80% cpu utilization on CPU0
Date: Wed, 24 Apr 2013 03:33:02 -0700

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 Based on the fact this only seems to happen on Intel Core architecture
 machines, I think this issue may be miscategorized.
 
 In my case, the flooding starts when I yank the VGA cable from the back of
 the machine. vgapci0 shares irq16 with ehci0 in every example of this issue
 i've been able to find.
 
 The forum thread on this issue may make for relevant reading:
 http://forums.freebsd.org/showthread.php?t=24952
 
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 <div dir=3D"ltr"><div><div>Based on the fact this only seems to happen on I=
 ntel Core architecture machines, I think this issue may be miscategorized.<=
 br><br></div>In my case, the flooding starts when I yank the VGA cable from=
  the back of the machine. vgapci0 shares irq16 with ehci0 in every example =
 of this issue i've been able to find.<br>
 <br></div>The forum thread on this issue may make for relevant reading: <a =
 href=3D"http://forums.freebsd.org/showthread.php?t=3D24952">http://forums.f=
 reebsd.org/showthread.php?t=3D24952</a><br></div>
 
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