[Gta04-owner] Bluetooth default speed?

Dr. H. Nikolaus Schaller hns at goldelico.com
Mon Apr 2 10:19:45 CEST 2012

Am 02.04.2012 um 10:03 schrieb Radek Polak:

> Hi,
> i have now working bluetooth in debian userspace. You just need to tell 


> bluetooth init script to launch hciattach:
> 	echo "-s 115200 /dev/ttyO0 any 115200 flow" > /etc/bluetooth/uart
> But the problem is that e.g. for A2DP audio the default speed (115200) is 
> unusable.

Yes, that is far too low.

> I can solve this easily for myself. Increase the speed, store it permanently 
> as documented here [1] and do:
> 	echo "-s 3000000 /dev/ttyO0 any 3000000 flow" > /etc/bluetooth/uart
> But from the distribution maker point of view, this is problem. I cant know 
> which speed to use. Either i can assume that everyone has slow speed, but then 
> the user experience will be bad. Or i can assume that everyone has configured 
> bluetooth for high speed.

Almost all GTA04A4 boards have been factory configured for 3 MBit/s.

Additionally, the hw-test script [2] tries to find out the current speed and
updates the default speed. So that that the 3 MBit/s speed is tested.

> What is best solution?

Well, it is possible to try different speeds but this process resets bluetooth
several times and takes up to 15 seconds. Or if you want to increase
complexity even more, you could also reprogram the speed... I.e. copy
this part from [2] into the distro.

But since I think this is only needed once on each device, it is not
necessary to carry it along into the far future.

> To me it looks like best solution to set up high speed for all new devices 
> (group tour) and let all existing users set high speed themselves. I can 
> supply  /etc/bluetooth/uart with the high speed then...

Yes, I would suggest to go this way.


> [1] http://projects.goldelico.com/p/gta04-kernel/page/Wireless/

[2]: http://git.goldelico.com/?p=gta04-rootfs.git;a=blob;f=debian/config/root/hw-test;h=3e58c015c5ecb837d9522fbd81e252facebd22b0;hb=HEAD

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