[dm-devel] Re: PROBLEM: powertop reports 8000 spurious interrupts/s from USB disk

[Matthew Dharm]

On Sun, May 04, 2008 at 07:24:19PM +0300, Marti Raudsepp wrote:
> Hello,
> 
> [1.] One line summary of the problem:
> PROBLEM: powertop reports 8000 spurious interrupts/s from USB disk
> 
> [2.] Full description of the problem/report:
> I am frequently seeing bursts of (exactly) 8000 interrupts per second
> from my USB controller; it seems to be closely related to activity on
> my USB hard disk, although the relation is somewhat vague.
> [...]
> What is obviously visible from the dstat output is that the ~8000
> interrupts keep arriving even when there is no actual activity on the
> disk, and it also causes no noticeable CPU load.

If there is no actual activity, then this is likely not a usb-storage
problem.  It may very well be an HCD problem, however.

You may want to turn on CONFIG_USB_STORAGE_DEBUG and verify that there is,
in fact, no activity to the drive during these events.

Matt

-- 
Matthew Dharm                              Home: mdharm-usb at one-eyed-alien.net 
Maintainer, Linux USB Mass Storage Driver

I'm a pink gumdrop! How can anything be worse?!!
					-- Erwin
User Friendly, 10/4/1998
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