GATT plugin

GATT plugin

[Tyler Arnold]

hi there ,
 I am building a GATT service/plugin for the bluetooth daemon and have
ported 5.27 bluez to my embedded ARM platform.

It seems like the GATT D-Bus API is not quite ready, so my options
appear to be either building the plugin and linking it as a statically
linked object or build it as a shared object library where the daemon
will pick it up from /usr/local/lib/bluetooth/plugins
Are both supported? I saw a message from about a year ago suggesting
the shared object approach was not the best path.

 thanks!

Re: GATT plugin

[Marcel Holtmann]

Hi Tyler,

> I am building a GATT service/plugin for the bluetooth daemon and have
> ported 5.27 bluez to my embedded ARM platform.
> 
> It seems like the GATT D-Bus API is not quite ready, so my options
> appear to be either building the plugin and linking it as a statically
> linked object or build it as a shared object library where the daemon
> will pick it up from /usr/local/lib/bluetooth/plugins
> Are both supported? I saw a message from about a year ago suggesting
> the shared object approach was not the best path.

actually I would prefer if we get the GATT D-Bus API ready so that you can use it. Have you tried it? I am actually curious to hear what would be missing.

Regards

Marcel

Re: GATT plugin

[Arman Uguray]

Hi Marcel,

> On Mon, Jan 26, 2015 at 10:11 PM, Marcel Holtmann <marcel@holtmann.org> wrote:
> Hi Tyler,
>
>> I am building a GATT service/plugin for the bluetooth daemon and have
>> ported 5.27 bluez to my embedded ARM platform.
>>
>> It seems like the GATT D-Bus API is not quite ready, so my options
>> appear to be either building the plugin and linking it as a statically
>> linked object or build it as a shared object library where the daemon
>> will pick it up from /usr/local/lib/bluetooth/plugins
>> Are both supported? I saw a message from about a year ago suggesting
>> the shared object approach was not the best path.
>
> actually I would prefer if we get the GATT D-Bus API ready so that you can use it. Have you tried it? I am actually curious to hear what would be missing.
>

The GATT D-Bus API was mostly implemented for client role a little
after the christmas release. I received push back on
StartNotify/StopNotify for an edge case and I haven't come up with an
alternative, so the API is behind the experimental flag and doesn't
support enabling notifications.

Server role support (over D-Bus) doesn't exist at all. If you run the
daemon with -E, you'll see the org.bluez.GattManager1 interface
exported but interacting with it virtually doesn't do anything.

The thing is, the upstream review process has been taking way too long
for us and we have some features to deliver, so I'm working on the
remaining features within the ChromiumOS tree for now. So you won't
see any patches from me any time soon. Last where I left off, we were
discussing replacing GattManager1 with a new GattProfile1 &
GattProfileManager1 API, so I may send out a proposal for that some
time next week.

Otherwise, that's where the API stands :)

Thanks,
Arman

Re: GATT plugin

[Marcel Holtmann]

Hi Arman,

>>> I am building a GATT service/plugin for the bluetooth daemon and have
>>> ported 5.27 bluez to my embedded ARM platform.
>>> 
>>> It seems like the GATT D-Bus API is not quite ready, so my options
>>> appear to be either building the plugin and linking it as a statically
>>> linked object or build it as a shared object library where the daemon
>>> will pick it up from /usr/local/lib/bluetooth/plugins
>>> Are both supported? I saw a message from about a year ago suggesting
>>> the shared object approach was not the best path.
>> 
>> actually I would prefer if we get the GATT D-Bus API ready so that you can use it. Have you tried it? I am actually curious to hear what would be missing.
>> 
> 
> The GATT D-Bus API was mostly implemented for client role a little
> after the christmas release. I received push back on
> StartNotify/StopNotify for an edge case and I haven't come up with an
> alternative, so the API is behind the experimental flag and doesn't
> support enabling notifications.
> 
> Server role support (over D-Bus) doesn't exist at all. If you run the
> daemon with -E, you'll see the org.bluez.GattManager1 interface
> exported but interacting with it virtually doesn't do anything.
> 
> The thing is, the upstream review process has been taking way too long
> for us and we have some features to deliver, so I'm working on the
> remaining features within the ChromiumOS tree for now. So you won't
> see any patches from me any time soon. Last where I left off, we were
> discussing replacing GattManager1 with a new GattProfile1 &
> GattProfileManager1 API, so I may send out a proposal for that some
> time next week.
> 
> Otherwise, that's where the API stands :)

actually I would prefer if we get this upstream quicker. And that applies to GATT client and GATT server support. I was under the assumption that Luiz was working on this as well. So what can we do to make this go faster?

One small detail here. I hope we are clear that "service" in LE GATT means the server side and "profile" in LE GATT is actually the client. The GATT server exposes a service and the profile explains how a GATT client uses it.

Regards

Marcel

Re: GATT plugin

[Arman Uguray]

Hi Marcel,

> On Tue, Jan 27, 2015 at 12:10 AM, Marcel Holtmann <marcel@holtmann.org> wrote:
> Hi Arman,
>
>>>> I am building a GATT service/plugin for the bluetooth daemon and have
>>>> ported 5.27 bluez to my embedded ARM platform.
>>>>
>>>> It seems like the GATT D-Bus API is not quite ready, so my options
>>>> appear to be either building the plugin and linking it as a statically
>>>> linked object or build it as a shared object library where the daemon
>>>> will pick it up from /usr/local/lib/bluetooth/plugins
>>>> Are both supported? I saw a message from about a year ago suggesting
>>>> the shared object approach was not the best path.
>>>
>>> actually I would prefer if we get the GATT D-Bus API ready so that you can use it. Have you tried it? I am actually curious to hear what would be missing.
>>>
>>
>> The GATT D-Bus API was mostly implemented for client role a little
>> after the christmas release. I received push back on
>> StartNotify/StopNotify for an edge case and I haven't come up with an
>> alternative, so the API is behind the experimental flag and doesn't
>> support enabling notifications.
>>
>> Server role support (over D-Bus) doesn't exist at all. If you run the
>> daemon with -E, you'll see the org.bluez.GattManager1 interface
>> exported but interacting with it virtually doesn't do anything.
>>
>> The thing is, the upstream review process has been taking way too long
>> for us and we have some features to deliver, so I'm working on the
>> remaining features within the ChromiumOS tree for now. So you won't
>> see any patches from me any time soon. Last where I left off, we were
>> discussing replacing GattManager1 with a new GattProfile1 &
>> GattProfileManager1 API, so I may send out a proposal for that some
>> time next week.
>>
>> Otherwise, that's where the API stands :)
>
> actually I would prefer if we get this upstream quicker. And that applies to GATT client and GATT server support. I was under the assumption that Luiz was working on this as well. So what can we do to make this go faster?
>

For me it's just a matter of long reviews and a general lack of
consensus on a finalized API, mostly due to the timezone difference.
Basically the whole review-revise-reupload cycle takes too long, with
a 12h delay between each email. The GATT D-Bus features are something
that we've all been working towards and it's high priority for
everybody then again I don't want to take another 6 months just
getting the basic external GATT service support merged.

Feature-wise, there are some points that Luiz raised about the way the
current API design handles notifications that we need to address.
Essentially, we want to have a reference counted way to enable remote
notifications (i.e. StartNotify/StopNotify) while also being able to
register a notification handler with shared/gatt-client immediately
after connection so that we can receive notifications that are sent
immediately. This makes things slightly tricky mainly because we don't
want to unnecessarily send notifications over D-Bus for a
characteristic if nobody requested to start them, but then if we wait
until an application calls StartNotify, some important notifications
might get missed.

Another point was regarding how external applications can manage the
lifetime of a connection and request things like auto-connect. There
is currently no GATT equivalent of "ConnectProfile/DisconnectProfile"
so if one app calls the regular Device.Disconnect, it will tear-down
the connection for everybody.

I think Luiz and I agreed that the above points can be addressed by
using a GattProfile1-like API, so that client-role applications can
register for certain types of behavior, pre-register for
notifications, enable auto-connect, etc.

Cheers,
Arman

Re: GATT plugin

[Luiz Augusto von Dentz]

Hi Marcel, Arman,

On Tue, Jan 27, 2015 at 10:10 AM, Marcel Holtmann <marcel@holtmann.org> wrote:
> Hi Arman,
>
>>>> I am building a GATT service/plugin for the bluetooth daemon and have
>>>> ported 5.27 bluez to my embedded ARM platform.
>>>>
>>>> It seems like the GATT D-Bus API is not quite ready, so my options
>>>> appear to be either building the plugin and linking it as a statically
>>>> linked object or build it as a shared object library where the daemon
>>>> will pick it up from /usr/local/lib/bluetooth/plugins
>>>> Are both supported? I saw a message from about a year ago suggesting
>>>> the shared object approach was not the best path.
>>>
>>> actually I would prefer if we get the GATT D-Bus API ready so that you can use it. Have you tried it? I am actually curious to hear what would be missing.
>>>
>>
>> The GATT D-Bus API was mostly implemented for client role a little
>> after the christmas release. I received push back on
>> StartNotify/StopNotify for an edge case and I haven't come up with an
>> alternative, so the API is behind the experimental flag and doesn't
>> support enabling notifications.
>>
>> Server role support (over D-Bus) doesn't exist at all. If you run the
>> daemon with -E, you'll see the org.bluez.GattManager1 interface
>> exported but interacting with it virtually doesn't do anything.
>>
>> The thing is, the upstream review process has been taking way too long
>> for us and we have some features to deliver, so I'm working on the
>> remaining features within the ChromiumOS tree for now. So you won't
>> see any patches from me any time soon. Last where I left off, we were
>> discussing replacing GattManager1 with a new GattProfile1 &
>> GattProfileManager1 API, so I may send out a proposal for that some
>> time next week.

Im surprised to hear that, I thought we were actually moving too fast
given the amount of regressions we have introduced and there are still
some left and lots of cleanups to do in the core and complete the unit
tests.

>> Otherwise, that's where the API stands :)
>
> actually I would prefer if we get this upstream quicker. And that applies to GATT client and GATT server support. I was under the assumption that Luiz was working on this as well. So what can we do to make this go faster?

Im doing the review as quick as I can, normally within 1-2 days, and
Im even fixing things myself to try to speed up the process.

> One small detail here. I hope we are clear that "service" in LE GATT means the server side and "profile" in LE GATT is actually the client. The GATT server exposes a service and the profile explains how a GATT client uses it.

That perhaps needs changes then, we start using GattService1 as client side API.

> Regards
>
> Marcel
>
> --
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-- 
Luiz Augusto von Dentz

Re: GATT plugin

[Arman Uguray]

Hi Luiz,

> On Tue, Jan 27, 2015 at 12:38 AM, Luiz Augusto von Dentz <luiz.dentz@gmail.com> wrote:
> Hi Marcel, Arman,
>
> On Tue, Jan 27, 2015 at 10:10 AM, Marcel Holtmann <marcel@holtmann.org> wrote:
>> Hi Arman,
>>
>>>>> I am building a GATT service/plugin for the bluetooth daemon and have
>>>>> ported 5.27 bluez to my embedded ARM platform.
>>>>>
>>>>> It seems like the GATT D-Bus API is not quite ready, so my options
>>>>> appear to be either building the plugin and linking it as a statically
>>>>> linked object or build it as a shared object library where the daemon
>>>>> will pick it up from /usr/local/lib/bluetooth/plugins
>>>>> Are both supported? I saw a message from about a year ago suggesting
>>>>> the shared object approach was not the best path.
>>>>
>>>> actually I would prefer if we get the GATT D-Bus API ready so that you can use it. Have you tried it? I am actually curious to hear what would be missing.
>>>>
>>>
>>> The GATT D-Bus API was mostly implemented for client role a little
>>> after the christmas release. I received push back on
>>> StartNotify/StopNotify for an edge case and I haven't come up with an
>>> alternative, so the API is behind the experimental flag and doesn't
>>> support enabling notifications.
>>>
>>> Server role support (over D-Bus) doesn't exist at all. If you run the
>>> daemon with -E, you'll see the org.bluez.GattManager1 interface
>>> exported but interacting with it virtually doesn't do anything.
>>>
>>> The thing is, the upstream review process has been taking way too long
>>> for us and we have some features to deliver, so I'm working on the
>>> remaining features within the ChromiumOS tree for now. So you won't
>>> see any patches from me any time soon. Last where I left off, we were
>>> discussing replacing GattManager1 with a new GattProfile1 &
>>> GattProfileManager1 API, so I may send out a proposal for that some
>>> time next week.
>
> Im surprised to hear that, I thought we were actually moving too fast
> given the amount of regressions we have introduced and there are still
> some left and lots of cleanups to do in the core and complete the unit
> tests.
>

Yep, there's definitely a lot of internal work to do, especially for
server-role. There are also regressions, though I believe we fixed
most of those (I saw a lot of your patches fly by, thanks for those).
I think I also have one patch that I need to rebase still.

>>> Otherwise, that's where the API stands :)
>>
>> actually I would prefer if we get this upstream quicker. And that applies to GATT client and GATT server support. I was under the assumption that Luiz was working on this as well. So what can we do to make this go faster?
>
> Im doing the review as quick as I can, normally within 1-2 days, and
> Im even fixing things myself to try to speed up the process.
>

I do very much appreciate that, but as I've expressed earlier, my
frustration ultimately has to do with the timezone difference. Even if
you reviewed it within an hour of seeing the patches, it will still
take me another 12-24 hours to see your response and address it.

>> One small detail here. I hope we are clear that "service" in LE GATT means the server side and "profile" in LE GATT is actually the client. The GATT server exposes a service and the profile explains how a GATT client uses it.
>
> That perhaps needs changes then, we start using GattService1 as client side API.
>
>> Regards
>>
>> Marcel
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
>
> --
> Luiz Augusto von Dentz

Thanks,
Arman