Fujitsu-Siemens Pocket Loox 718/720 users attention: Found a bad BT PAN-related bug in the Bluetooth implementation (Widcomm 1.5

Upon testing the multiplayer capabilities of the new, 1.2 version of Fast Sudoku by PPCLink, I’ve run into a problem of increased CPU cycle usage when operating in Bluetooth PAN mode on my Fujitsu-Siemens Pocket Loox 720. Then, if you initiate a BT PAN connection from your Pocket Loox 720, the CPU usage of the Bluetooth Manager application may be pretty high.

This problem is particularly visible if you have more than 3-4 Bluetooth icons on the main screen of your Bluetooth Manager. Then, if you have for example 10-15 icons, the CPU usage may be as high as 20%, which is a major problem (it causes a generic slowdown and an increased battery consumption).

Affected devices

The Fujitsu-Siemens Pocket Loox 718/720 for sure. Some other Widcomm-based devices may also be affected. I don’t know if other Pocket PC’s (not just the Pocket Loox 718/720) with the Widcomm 1.5.0 (build 1800) are affected by the problem – you may want to check it yourself.

The following Widcomm-based devices are not affected by the problem (I’ve tested):

HP iPAQ 2210 (1.4.1 build 60)
HP iPAQ hx4700 with WM5 (1.7.1 build 3400)
The current (0.50) version of the Dell Axim (WM5) x50(v)/x51(v) BT stack (1.7.1 build 3400) hack

Also, none of the Microsoft BT stack-based devices are affected (all HTC models, for example).

The solution

Either build up the BT PAN from another Pocket PC so that you don’t need to start Bluetooth Manager on the Loox, or, make sure you kill it (by any task manager) after invoking it for the BT PAN to be started. Reducing the number of icons also works but not as good as just killing Bluetooth Manager – the latter will consume some 2-3% CPU time even with only 1-2 icon in the Bluetooth Manager.

That is, it’s the best to kill Bluetooth Manager after building up BT PAN if you don’t want to have the above-described problems.