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On 2008-03-31T03:13:41+00:00 William wrote:

Description of problem:
powertop is showing that ehci_work is waking up the CPU 10 times per second all
the time with more recent kernels.  Besides, there are new culprits like <kernel
IPI> : Rescheduling interrupts that didn't showed up with previous kernels.

Version-Release number of selected component (if applicable):
Live Image on a USB stick of Fedora Rawhide Snapshot 20080328 released a few
days ago.  This is also happening in Fedora 8 with the latest updates (post
2.6.23 kernels)


How reproducible:
Always, just open powertop and you will always see the following line:
45.3% ( 10.0)     <kernel core> : ehci_work (ehci_watchdog)


Actual results:
The CPU can't sleep for longer periods of time so it can't save power,
decreasing battery life and increasing the electricity bill.


Expected results:
There should be no wakeups.  It didn't showed on 2.6.23 kernels so it's
something that should be fixed ASAP.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/0

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On 2008-03-31T03:19:25+00:00 William wrote:

Created attachment 299670
powertop output for the command line

I collected this with the following command:
   # sleep 5 ; powertop -d 20

This is running the Fedora Rawhide Snapshot on a USB stick in init 3, then I
disabled a few services just for the sake of taking wake ups to a minimum.

Here you can see that it would have been an excellent 3 wps or less if it not
were for this bug (ehci_work) showing up in the stats.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/1

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On 2008-03-31T03:28:42+00:00 Dave wrote:

it's probably something periodically waking up to do disk IO (and hence waking
up the usb stick).


Reply at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/2

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On 2008-03-31T03:31:33+00:00 William wrote:

Created attachment 299684
powertop output for the gnome desktop

Again, I collected this with the following command using gnome-terminal:
   # sleep 5 ; powertop -d 20

This is running the Fedora Rawhide Snapshot on a USB stick in init 5, the only
thing I disabled was the wireless networking in NetworkManager so the iwl3945
driver doesn't show up here.

Note that there is a new entry I didn't see before with previous kernels:
21.8% (  4.8)      <kernel IPI> : Rescheduling interrupts

What is that? what is the definition of IPI? I guess this is something new in
the kernel.

Besides this there is another one: <kernel IPI> : TLB shootdowns but it doesn't
show up high in the stats.

Another thing, this bug is in Fedora 8 with the latest updates too but the
entry in powertop looks like this:
5,9% ( 10,0)      nash-hotplug : ehci_irq (ehci_watchdog)

I guess this is the same problem.  What it nash-hotplug?? I can't see any
process running with that name.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/3

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On 2008-03-31T03:34:56+00:00 William wrote:

Dave, so the only way to confirm this is installing Rawhide on the hard drive??
or may be using the Live CD instead of the USB stick??

I wonder if you see the same thing on your laptop or this is just me.

I am using a Dell XPS M1210 laptop with Intel Core Duo ICH7 chipset.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/4

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On 2008-05-14T08:27:56+00:00 Bug wrote:

Changing version to '9' as part of upcoming Fedora 9 GA.
More information and reason for this action is here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/5

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On 2008-11-06T03:20:38+00:00 William wrote:

Well, this still happens in Fedora 10 Preview.

On my laptop (Dell XPS M1210) I just realized that it was due to the
uvcvideo driver for the webcam.  Removing that driver solves the wake
ups.

But, on my desktop computer (Dell XPS 420 Quad Core) it uses the same
driver because my 22" LCD monitor has a compatible webcam, I remove the
driver but it doesn't solve the wake ups.

So, what else can I do to figure out the real source in this case? Maybe
is it because of the mouse and keyboard being connected to an USB port?

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/6

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On 2008-11-26T02:11:24+00:00 Bug wrote:


This bug appears to have been reported against 'rawhide' during the Fedora 10 
development cycle.
Changing version to '10'.

More information and reason for this action is here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/7

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On 2009-07-17T21:06:29+00:00 William wrote:

Ok, this is a driver problem and every time I power up my laptop y have
to "modprobe -r uvcvideo" to reduce the power consumption.  As I said in
my first comment the module wakes up the cpu 10 times per second.

This problem is being worked upstream by Laurent Pinchart y Matthew Garrett:
http://bugzilla.kernel.org/show_bug.cgi?id=11948

It would be nice if the kernel can handle this situation automatically
and save power while the webcam is not being used.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/11

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On 2010-04-27T11:58:34+00:00 Bug wrote:


This message is a reminder that Fedora 11 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
and issuing updates for Fedora 11.  It is Fedora's policy to close all
bug reports from releases that are no longer maintained.  At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
'version' of '11'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version prior to Fedora 11's end of life.

Bug Reporter: Thank you for reporting this issue and we are sorry that 
we may not be able to fix it before Fedora 11 is end of life.  If you 
would still like to see this bug fixed and are able to reproduce it 
against a later version of Fedora please change the 'version' of this 
bug to the applicable version.  If you are unable to change the version, 
please add a comment here and someone will do it for you.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events.  Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

The process we are following is described here: 
http://fedoraproject.org/wiki/BugZappers/HouseKeeping

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/24

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On 2010-06-28T10:34:08+00:00 Bug wrote:


Fedora 11 changed to end-of-life (EOL) status on 2010-06-25. Fedora 11 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of 
Fedora please feel free to reopen this bug against that version.

Thank you for reporting this bug and we are sorry it could not be fixed.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/315362/comments/25


** Changed in: linux (Fedora)
       Status: Confirmed => Won't Fix

** Changed in: linux (Fedora)
   Importance: Unknown => Medium

** Bug watch added: Linux Kernel Bug Tracker #11948
   https://bugzilla.kernel.org/show_bug.cgi?id=11948

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/315362

Title:
  scan_async (ehci_watchdog) wakes up the CPU

Status in linux package in Ubuntu:
  Won't Fix
Status in linux package in Fedora:
  Won't Fix

Bug description:
  Dell XPS 1330

  Ubuntu Intrepid
  Linux torkiano-laptop 2.6.27-11-generic #1 SMP Thu Jan 8 08:38:38 UTC 2009 
x86_64 GNU/Linux

  powertop is showing that scan_async is waking up the CPU 10 times per
  second all the time with more recent kernels.  Besides, there are new
  culprits like <kernel IPI> : Rescheduling interrupts that didn't
  showed up with previous kernels.

   7,7% ( 30,5)      <kernel IPI> : Rescheduling interrupts 
  1,0% ( 10,0)         <kernel core> : scan_async (ehci_watchdog)

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