[Bluez-users] inquiry scan problems

[Bluez-users] inquiry scan problems

[Marco Trudel]

Hello everybody

After i noticed the problems (description follows), i updated the 
software to the most recent versions. Now I have:
- kernel 2.6.8-24
- bluez-libs-2.11.tar.gz
- bluez-utils-2.11.tar.gz
- bluez-hcidump-1.15.tar.gz
- avetanabt-20041119 (http://sourceforge.net/projects/avetanabt/)
-> acer bt500 usb dongle

My goal is to get a list of all bluetooth devices in rainge. I do five 
inquirys in a row (with one second break between two complete scans).
The problems now are:

- the inquiry doesn't always find all devices
that raises the question: how reliable/secure is it that all devices are 
found in an inquiry? how possible is that one or more devices are missed?

- the fife inquirys sometimes stop in the middle and won't continue.
for example after starting the 3. inquiry, it never completes (comes to 
[public void inquiryCompleted(int status)] (jsr82)

- [RemoteDevice].getFriendlyName(true) sometimes (well - in fact often) 
returns the String "null" (not null object) instead of the real friendly 
name. if i do a loop with getFriendlyName(true), after ~8 times it gets 
the correct friendlyName...
the null (object) should only be returned if the hardware doesn't 
support getting the friendlyName (but obviusly this works). i have no 
idea why the "null" string is supposed to be returned...
I added the hcidump of a request with "null" returns... maybe someone of 
you can do more with it than me...

- [RemoteDevice].getFrienlyName(true) returns a friendly name of another 
device if multiple devices are in rainge.

- general question: what if multiple bluetooth devices are connected to 
the computer. which level has to support that?
bluez / avetana (jsr82 implementation)?


I don't know which one of the problems are a subject of bluez.
If it's not a bluez subject, i would appreciate if someone could point 
me to the source of the problem.

I assume the usb dongle is the problem here. Someone on this mailinglist 
already mentioned that it's a crappy dongle. (thanks again for the time 
you invested - you really helped me a lot!)
If it's the dongle again, what do other users here use? which ones work 
reliably?

please let me know if you need additional informations...


kind regards
Marco Trudel



hcidump:
(please note, every friendlyName is (intentinally) requested twice.
--------------------
< HCI Command: Inquiry (0x01|0x0001) plen 5
 > HCI Event: Command Status (0x0f) plen 4
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Result (0x02) plen 15
 > HCI Event: Inquiry Complete (0x01) plen 1
 > HCI Event: Command Complete (0x0e) plen 3
< HCI Command: Remote Name Request (0x01|0x0019) plen 10
 > HCI Event: Command Status (0x0f) plen 4
 > HCI Event: Remote Name Req Complete (0x07) plen 255
< HCI Command: Remote Name Request (0x01|0x0019) plen 10
 > HCI Event: Command Complete (0x0e) plen 3
 > HCI Event: Command Status (0x0f) plen 4
< HCI Command: Remote Name Request (0x01|0x0019) plen 10
 > HCI Event: Command Status (0x0f) plen 4
 > HCI Event: Remote Name Req Complete (0x07) plen 255
< HCI Command: Remote Name Request (0x01|0x0019) plen 10
 > HCI Event: Command Complete (0x0e) plen 3
 > HCI Event: Command Status (0x0f) plen 4
< HCI Command: Remote Name Request (0x01|0x0019) plen 10
 > HCI Event: Command Status (0x0f) plen 4
 > HCI Event: Remote Name Req Complete (0x07) plen 255
< HCI Command: Remote Name Request (0x01|0x0019) plen 10
 > HCI Event: Command Complete (0x0e) plen 3
 > HCI Event: Command Status (0x0f) plen 4
--------------------


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Re: [Bluez-users] inquiry scan problems

[Marcel Holtmann]

Hi Marco,

> My goal is to get a list of all bluetooth devices in rainge. I do five 
> inquirys in a row (with one second break between two complete scans).
> The problems now are:
> 
> - the inquiry doesn't always find all devices
> that raises the question: how reliable/secure is it that all devices are 
> found in an inquiry? how possible is that one or more devices are missed?
> 
> - the fife inquirys sometimes stop in the middle and won't continue.
> for example after starting the 3. inquiry, it never completes (comes to 
> [public void inquiryCompleted(int status)] (jsr82)
> 
> - [RemoteDevice].getFriendlyName(true) sometimes (well - in fact often) 
> returns the String "null" (not null object) instead of the real friendly 
> name. if i do a loop with getFriendlyName(true), after ~8 times it gets 
> the correct friendlyName...
> the null (object) should only be returned if the hardware doesn't 
> support getting the friendlyName (but obviusly this works). i have no 
> idea why the "null" string is supposed to be returned...
> I added the hcidump of a request with "null" returns... maybe someone of 
> you can do more with it than me...
> 
> - [RemoteDevice].getFrienlyName(true) returns a friendly name of another 
> device if multiple devices are in rainge.
> 
> - general question: what if multiple bluetooth devices are connected to 
> the computer. which level has to support that?
> bluez / avetana (jsr82 implementation)?

can your reproduce it without using any JSR-82 stuff?

> I don't know which one of the problems are a subject of bluez.
> If it's not a bluez subject, i would appreciate if someone could point 
> me to the source of the problem.
> 
> I assume the usb dongle is the problem here. Someone on this mailinglist 
> already mentioned that it's a crappy dongle. (thanks again for the time 
> you invested - you really helped me a lot!)
> If it's the dongle again, what do other users here use? which ones work 
> reliably?

This is the Zeevo TC2001 based dongle, right? If yes, then replace it,
because I won't rely on this hardware.

Regards

Marcel




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Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/
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