Add SDP discovery support to gatttool with BR

Add SDP discovery support to gatttool with BR

[Vikrampal]

Hi,

I am new to BlueZ community. I'd like to contribute to BlueZ community. I
went through BlueZ's TODO items. 
To get started, I have selected adding SDP discovery support to gatttool
with BR as my first work.

- Add sdp discovery support to gatttool with BR (--sdp, default is 0x1f)

There are several options available under SDP support. However, this TODO
particular item seeks to support only search option.

Please provide me your valuable suggestion for the same. Thanks!

Regards,
Vikram

Re: Add SDP discovery support to gatttool with BR

[Dmitry Kasatkin]

On 08/05/14 11:44, Vikrampal wrote:
> Hi,
>
> I am new to BlueZ community. I'd like to contribute to BlueZ community. I
> went through BlueZ's TODO items. 
> To get started, I have selected adding SDP discovery support to gatttool
> with BR as my first work.
>
> - Add sdp discovery support to gatttool with BR (--sdp, default is 0x1f)
>
> There are several options available under SDP support. However, this TODO
> particular item seeks to support only search option.
>
> Please provide me your valuable suggestion for the same. Thanks!
>
> Regards,
> Vikram
>
>

Hi Marcel and Johan,

Vikrant is keen to contribute to BlueZ.
Does it make sense to start with what Vikrant suggest?
Anybody working on that?

BR,

Dmitry

Re: Add SDP discovery support to gatttool with BR

[Johan Hedberg]

Hi Vikram,

On Thu, May 08, 2014, Vikrampal wrote:
> I am new to BlueZ community. I'd like to contribute to BlueZ community. I
> went through BlueZ's TODO items. 
> To get started, I have selected adding SDP discovery support to gatttool
> with BR as my first work.
> 
> - Add sdp discovery support to gatttool with BR (--sdp, default is 0x1f)

Not sure what exactly you mean here. ATT over BR/EDR uses a fixed PSM so
separate discovery of this is not necessary. The core spec says:

"The use of a fixed PSM allows rapid reconnection of the L2CAP channel
for Attribute Protocol as a preliminary SDP query is not required."

Based on git blame this item was added 5th Oct 2010, i.e. in the very
early days of the LE specification. I suspect that there might have been
some confusion regarding the ATT PSM back then. While this kind of PSM
discovery it's not completely pointless, we don't do it for any other
fixed PSM profiles either (e.g. A2DP & AVRCP) so I think it's better to
spend time on more valuable tasks instead.

I've now removed the ATT PSM related items from the TODO file (which btw
could use much more cleanups in general).

Johan

RE: Add SDP discovery support to gatttool with BR

[Vikrampal]

Hi Johan,

>-----Original Message-----
>From: Johan Hedberg [mailto:johan.hedberg@gmail.com] 
>Sent: Wednesday, May 14, 2014 1:26 PM
>To: Vikrampal
>Cc: linux-bluetooth@vger.kernel.org; Dmitry Kasatkin;
bharat.panda@samsung.com; p.sinha@samsung.com; cpgs@samsung.com
>Subject: Re: Add SDP discovery support to gatttool with BR
>
>Hi Vikram,
>
>On Thu, May 08, 2014, Vikrampal wrote:
>> I am new to BlueZ community. I'd like to contribute to BlueZ 
>> community. I went through BlueZ's TODO items.
>> To get started, I have selected adding SDP discovery support to 
>> gatttool with BR as my first work.
>> 
>> - Add sdp discovery support to gatttool with BR (--sdp, default is 
>> 0x1f)
>
>Not sure what exactly you mean here. ATT over BR/EDR uses a fixed PSM so
separate discovery of this is not necessary. The core spec says:
>
>"The use of a fixed PSM allows rapid reconnection of the L2CAP channel for
Attribute Protocol as a preliminary SDP query is not required."
>
>Based on git blame this item was added 5th Oct 2010, i.e. in the very early
days of the LE specification. I suspect that there might have been some
confusion regarding >the ATT PSM back then. While this kind of PSM discovery
it's not completely pointless, we don't do it for any other fixed PSM
profiles either (e.g. A2DP & AVRCP) so I >think it's better to spend time on
more valuable tasks instead.
>
>I've now removed the ATT PSM related items from the TODO file (which btw
could use much more cleanups in general).
>
>Johan

Thanks for your kind advice. Could you please suggest me as to which all
topics are of more value currently so that
I may pick up one of them as my maiden contribution. 

Regards,
Vikram