[pulseaudio-discuss] bluetooth: problem with old headset

Georg Chini georg at chini.tk
Fri Mar 13 00:36:00 PDT 2015

On 04.03.2015 08:42, Georg Chini wrote:
> On 02.03.2015 23:02, Georg Chini wrote:
>> On 02.03.2015 07:41, Georg Chini wrote:
>>> On 23.02.2015 09:06, David Henningsson wrote:
>>>> On 2015-02-21 23:14, Georg Chini wrote:
>>>>> Hello,
>>>>> With the Plantronics 590, the connect() call in bluez5_sco_acquire_cb
>>>>> returns
>>>>> "Protocol not supported". The headset itself is functional, I tested
>>>>> with my mobile.
>>>> I've heard of this, but never seen it myself. I suspect it's a 
>>>> kernel regression, but I'm not sure. Does it work with older 
>>>> kernels? Like, one, two, three years old kernels or such?
>> Yes, it is a kernel regression introduced in 3.12. There are two 
>> reasons why it does no longer
>> work:
>> 1) The driver expects the headset to issue a sync connection finished 
>> event (0x2c), even
>> if the connection attempt fails, so that it can test various packet 
>> types until it succeeds.
>> My old headset does not do so, it just sends a command status event 
>> (0x0f) with the
>> status code 0x1a. So the driver tries its first option and then fails.
>> 2) The headset apparently needs a retrans_effort of 0xff (whatever 
>> that parameter means)
>> instead of 0x01.
I just noticed that this has already been fixed in 3.18, sorry for the 

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