[Bluez-users] indication of Class 1 or Class 2 devices

[Bluez-users] indication of Class 1 or Class 2 devices

[Russell Senior]

Is there a way, via /proc or /sys or something to discover whether a
bluetooth device is Class 1 (100m) or Class 2 (10m)?

Thanks.


-- 
Russell Senior         ``I have nine fingers; you have ten.''
seniorr@aracnet.com


-------------------------------------------------------
This SF.Net email is sponsored by:
Power Architecture Resource Center: Free content, downloads, discussions,
and more. http://solutions.newsforge.com/ibmarch.tmpl
_______________________________________________
Bluez-users mailing list
Bluez-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bluez-users

Re: [Bluez-users] indication of Class 1 or Class 2 devices

[Marcel Holtmann]

Hi Russell,

> Is there a way, via /proc or /sys or something to discover whether a
> bluetooth device is Class 1 (100m) or Class 2 (10m)?

the simple answer is no.

Regards

Marcel




-------------------------------------------------------
This SF.Net email is sponsored by:
Power Architecture Resource Center: Free content, downloads, discussions,
and more. http://solutions.newsforge.com/ibmarch.tmpl
_______________________________________________
Bluez-users mailing list
Bluez-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bluez-users

Re: [Bluez-users] indication of Class 1 or Class 2 devices

[Peter Stephenson]

Russell Senior wrote:
> Is there a way, via /proc or /sys or something to discover whether a
> bluetooth device is Class 1 (100m) or Class 2 (10m)?

It's actually pretty difficult even if you have low level access to
the device, never mind via the OS.  There's no standardised way of
providing the information, and in the simplest case the module
manufacturer may simply have stuck a power amplifier onto the
transmitter.  If they do that they are supposed to provide
enough information for the device to support power control, however,
so if you can get access to that information you should be able to tell.

If it's a CSR device, you can find an interface to persistent store and
look at PSKEY_LC_POWER_TABLE (0x001e) or PSKEY_LC_ENHANCED_POWER_TABLE (for
devices with EDR, 0x0031).

Otherwise, you're stuck with seeing what power it's actually outputting
at its maximum setting by using a remote device and some measurement
equipment.

By far the easiest way is to go 100m away with another class 1 device
and see if it stays connected.  (Of course, you may be simply
testing the receiver sensitivity; in good conditions you can get
a lot more than 100m as a maximum once you're connected.)

pws


This message has been scanned for viruses by BlackSpider MailControl - www.blackspider.com


-------------------------------------------------------
This SF.Net email is sponsored by:
Power Architecture Resource Center: Free content, downloads, discussions,
and more. http://solutions.newsforge.com/ibmarch.tmpl
_______________________________________________
Bluez-users mailing list
Bluez-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bluez-users

Re: [Bluez-users] indication of Class 1 or Class 2 devices

[Steven Singer]

Peter Stephenson wrote:
> Russell Senior wrote:
>> Is there a way, via /proc or /sys or something to discover whether a
>> bluetooth device is Class 1 (100m) or Class 2 (10m)?
> 
> It's actually pretty difficult even if you have low level access to
> the device, never mind via the OS.  There's no standardised way of
> providing the information, and in the simplest case the module
> manufacturer may simply have stuck a power amplifier onto the
> transmitter.  If they do that they are supposed to provide
> enough information for the device to support power control, however,
> so if you can get access to that information you should be able to tell.

In theory, there's the HCI command Read_Transmit_Power_Level. Once a
link is up it should tell you the current power level and the maximum
power level.

If the remote device doesn't support power control then the local
device will be limited to class 2 power even if it supports class 1.

Of course, this assumes that the module manufacturer has entered the
correct numbers in the configuration data in the module. If they've
stuch a power amplifier on and not updated the data then the chip may
be reporting the power before the power amplifier.

> If it's a CSR device, you can find an interface to persistent store and
> look at PSKEY_LC_POWER_TABLE (0x001e) or PSKEY_LC_ENHANCED_POWER_TABLE (for
> devices with EDR, 0x0031).

The BCCMD max_tx_power (0x6827) might do the right thing on some
versions of firmware.

	- Steven
-- 


This message has been scanned for viruses by BlackSpider MailControl - www.blackspider.com


-------------------------------------------------------
This SF.Net email is sponsored by:
Power Architecture Resource Center: Free content, downloads, discussions,
and more. http://solutions.newsforge.com/ibmarch.tmpl
_______________________________________________
Bluez-users mailing list
Bluez-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bluez-users