[ltp] Fingerprint reader occasionally gets hot (T61)
Daniel Castro
linux-thinkpad@linux-thinkpad.org
Fri, 01 Aug 2008 18:26:07 +0100
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Nice. I added this to ThinkWiki.
http://www.thinkwiki.org/wiki/How_to_enable_the_fingerprint_reader_with_ThinkFinger#Fix_for_the_fingerprint_reader_getting_too_hot
________________________
Daniel Castro
Networking and Distributed Systems
Computer Science
Trinity College Dublin
Mobile: 083-318-2058
86.4.3 Trinity Hall, Dartry Road, Dublin 6
________________________
Tino Keitel wrote:
> On Fri, Aug 01, 2008 at 11:58:52 +0100, Daniel Castro wrote:
>
>> Hello,
>>
>> I have noticed that the fingerprint reader gets hot some times. My HDD
>> is under the reader and I'm sure it is not the HDD what is making it
>> warm-up.
>> Does anyone else has experienced this? How to know why this is
>> happening? What to do to cool it down?
>> As I said this happens occasionally, and the reader works flawlessly for
>> me, I use it a lot. It's just a bit uncomfortable to have that hot thing
>> in my palm.
>>
>
> I gues that the fingerprint reader USB device hasn't autosuspend
> enabled, so it is "on" all the time.
>
> Try this:
>
> $ for i in `find /sys/devices/*/*/usb* -name level` ; do echo -n "$i: " ; cat $i ; done
>
> If there is one ore more device in state "on", use lsusb to get the
> vendor/device ID of the fingerprint reader, and check if it matches one
> of the devices in state "on". Example:
>
> output of the above for loop:
>
> /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/power/level: on
>
> check vendor/device ID:
>
> $ cat /sys/devices/pci0000\:00/0000\:00\:1d.7/usb1/1-1/1-1.1/idVendor
> 04d9
> $ cat /sys/devices/pci0000\:00/0000\:00\:1d.7/usb1/1-1/1-1.1/idProduct
> 1400
>
> If you spotted the sysfs device that matches the fingerprint reader, to
> this:
>
> echo "auto" > /sys/<path-to-device>/power/level
>
> After this, the fingerprint reader should be in state "autosuspend" and
> don't get got anymore.
>
> For a short ckeck, you can also use powertop -d and watch the USB
> status output. This works with powertop 1.10 and above.
>
> I just disabled the fingerprint reader in the BIOS as it is insecure
> anyway.
>
> Regards,
> Tino
>
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Nice. I added this to ThinkWiki.<br>
<a class="moz-txt-link-freetext" href="http://www.thinkwiki.org/wiki/How_to_enable_the_fingerprint_reader_with_ThinkFinger#Fix_for_the_fingerprint_reader_getting_too_hot">http://www.thinkwiki.org/wiki/How_to_enable_the_fingerprint_reader_with_ThinkFinger#Fix_for_the_fingerprint_reader_getting_too_hot</a><br>
<br>
<pre class="moz-signature" cols="72">________________________
Daniel Castro
Networking and Distributed Systems
Computer Science
Trinity College Dublin
Mobile: 083-318-2058
86.4.3 Trinity Hall, Dartry Road, Dublin 6
________________________
</pre>
<br>
<br>
Tino Keitel wrote:
<blockquote cite="mid:20080801122758.GA3545@dose.home.local" type="cite">
<pre wrap="">On Fri, Aug 01, 2008 at 11:58:52 +0100, Daniel Castro wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hello,
I have noticed that the fingerprint reader gets hot some times. My HDD
is under the reader and I'm sure it is not the HDD what is making it
warm-up.
Does anyone else has experienced this? How to know why this is
happening? What to do to cool it down?
As I said this happens occasionally, and the reader works flawlessly for
me, I use it a lot. It's just a bit uncomfortable to have that hot thing
in my palm.
</pre>
</blockquote>
<pre wrap=""><!---->
I gues that the fingerprint reader USB device hasn't autosuspend
enabled, so it is "on" all the time.
Try this:
$ for i in `find /sys/devices/*/*/usb* -name level` ; do echo -n "$i: " ; cat $i ; done
If there is one ore more device in state "on", use lsusb to get the
vendor/device ID of the fingerprint reader, and check if it matches one
of the devices in state "on". Example:
output of the above for loop:
/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.1/power/level: on
check vendor/device ID:
$ cat /sys/devices/pci0000\:00/0000\:00\:1d.7/usb1/1-1/1-1.1/idVendor
04d9
$ cat /sys/devices/pci0000\:00/0000\:00\:1d.7/usb1/1-1/1-1.1/idProduct
1400
If you spotted the sysfs device that matches the fingerprint reader, to
this:
echo "auto" > /sys/<path-to-device>/power/level
After this, the fingerprint reader should be in state "autosuspend" and
don't get got anymore.
For a short ckeck, you can also use powertop -d and watch the USB
status output. This works with powertop 1.10 and above.
I just disabled the fingerprint reader in the BIOS as it is insecure
anyway.
Regards,
Tino
</pre>
</blockquote>
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