[maemo-users] [maemo-users] Bluetooth stops working

From: Nils Faerber nils.faerber at kernelconcepts.de
Date: Wed Feb 8 17:54:09 EET 2006
Hash: SHA1

Frantisek Dufka schrieb:
> Peter Westerström wrote:
>> The same happens when I'm using my bluetooth keyboard. After a while I
>> can no longer connect it.
>> I'm using 3.2005.51-13.
>> Have anyone else experienced similar problems?
> BTW there is also something strange with wi-fi vs bluetooth in all
> firmwares I had so far see
> https://maemo.org/bugzilla/show_bug.cgi?id=326 looks like in heavy
> bluetooth usage (hcitool scan,sdptool browse) wi-fi connection drops.

This could be a firmware bug in the WLAN module as well...
WIFI and Bluetooth use the same frequency spectrum of 2.4GHz. Bluetooth
usually does not interfere with WIFIsince it uses very rapid channel
switch (up to 1200 channel switches per second).
But if you do an inquiry the Bluetooth module will almost broadcast
inquiry packets on all of those channels almost at once to catch modules
in its range. The inquiry scan algorithm is quite scary ;)
So inquiry cause a lot of noise in the 2.4GHz spectrum.
What could happen is that the WIFI firmware does not handle
receive/transmit faults too well. So under certain circumstance while
doing an inquiry a WIFI packet might get messed up quite badly without
the radio detecting a signal drop (because in fact it had a good carrier
all the time). Probably the same fault could be triggered with a high
traffic WIFI cell...

> Frantisek
  nils faerber

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