Hi,
I was trying to write some code to continuously scan the bluetooth field
for bluetooth devices sending advertising packets (ie beacon-mode).
These devices would come and go so I wanted to avoid the cache.
I noticed the D-Bus interface doesn't quite allow me to do this (as it
caches the devices and I can't monitor the RSSI field). But I think the
bluetooth management interface does. Is that the correct approach?
Cheers,
Don
On Tue, Nov 29, 2016 at 01:28:42PM -0800, Brennan Ashton wrote:
> >
> > Sorry for being ignorant (as I can't quite find the filter duplicate
> > code
> > other than the setting of the bit), but would throttling work
> > here? Cap the
> > duplicates at say every 100ms or 10x/second. That probably won't
> > help with
> > power consumption (unless start/stop of the radio is quick?).
> >
> > Just trying to help move this along.. willing to code/test.
> >
> > Cheers,
> > Don
> >
> The thread I mentioned is here:
> https://marc.info/?t=147345134200002&r=1&w=2
>
> The constant of interest is this LE_SCAN_FILTER_DUP_ENABLE. I had to
> recompile with this disabled because I never wanted the filter for my
> application. I had proposed making this an option in the adaptor
> interface, but there did not seem to be any interest.
Hi Brennan,
Looking through the code, I am guessing you hacked up
net/bluetooth/hci_request.c::active_scan to set enable_cp.filter_dup = 0?
How did that turn out? Was there a lot of volume?
I am running 'hcitool lescan --duplicates' with a couple of cc2650 tags I
have (one custom fw) and see about 20-25 adv/second. That doesn't seem so
bad.
What type of numbers did you see?
Cheers,
Don
On Tue, 2016-11-29 at 16:36 -0500, Don Zickus wrote:
> On Tue, Nov 29, 2016 at 01:28:42PM -0800, Brennan Ashton wrote:
> >
> > >
> > > >
> > > > I have had to resort to using the HCI interface to work with
> > > > scanning
> > > > and advertising beacon packets. I had mentioned in an earlier
> > > > thread
> > > > the issue with duplicates. Not only do you end up with a lot
> > > > of
> > > > spam
> > > > on the dbus interface you end up with an ever increasing number
> > > > of
> > > > bluetooth devices. The Bluetooth mesh uses this transport, so
> > > > I
> > > > really
> > > > would like to see a nice interface to support rx/tx of these
> > > > packets.
> > >
> > > Hi,
> > >
> > > Sorry for being ignorant (as I can't quite find the filter
> > > duplicate
> > > code
> > > other than the setting of the bit), but would throttling work
> > > here? Cap the
> > > duplicates at say every 100ms or 10x/second. That probably won't
> > > help with
> > > power consumption (unless start/stop of the radio is quick?).
> > >
> > > Just trying to help move this along.. willing to code/test.
> > >
> > > Cheers,
> > > Don
> > >
> > The thread I mentioned is here:
> > https://marc.info/?t=147345134200002&r=1&w=2
> >
> > The constant of interest is this LE_SCAN_FILTER_DUP_ENABLE. I had
> > to
> > recompile with this disabled because I never wanted the filter for
> > my
> > application. I had proposed making this an option in the adaptor
> > interface, but there did not seem to be any interest.
>
> Hi Brennan,
>
> Yup, I saw that thread earlier and that flag. I wasn't sure how that
> flag
> was being propagated. Does it go right to the device? I guess I
> thought
> the kernel was filtering duplicates, but perhaps not?
>
> Cheers,
> Don
It is set in all the LE_SET_SCAN_ENABLE HCI requests so the device is
doing the actual filtering.
On Tue, Nov 29, 2016 at 01:28:42PM -0800, Brennan Ashton wrote:
> > > I have had to resort to using the HCI interface to work with
> > > scanning
> > > and advertising beacon packets. I had mentioned in an earlier
> > > thread
> > > the issue with duplicates. Not only do you end up with a lot of
> > > spam
> > > on the dbus interface you end up with an ever increasing number of
> > > bluetooth devices. The Bluetooth mesh uses this transport, so I
> > > really
> > > would like to see a nice interface to support rx/tx of these
> > > packets.
> >
> > Hi,
> >
> > Sorry for being ignorant (as I can't quite find the filter duplicate
> > code
> > other than the setting of the bit), but would throttling work
> > here? Cap the
> > duplicates at say every 100ms or 10x/second. That probably won't
> > help with
> > power consumption (unless start/stop of the radio is quick?).
> >
> > Just trying to help move this along.. willing to code/test.
> >
> > Cheers,
> > Don
> >
> The thread I mentioned is here:
> https://marc.info/?t=147345134200002&r=1&w=2
>
> The constant of interest is this LE_SCAN_FILTER_DUP_ENABLE. I had to
> recompile with this disabled because I never wanted the filter for my
> application. I had proposed making this an option in the adaptor
> interface, but there did not seem to be any interest.
Hi Brennan,
Yup, I saw that thread earlier and that flag. I wasn't sure how that flag
was being propagated. Does it go right to the device? I guess I thought
the kernel was filtering duplicates, but perhaps not?
Cheers,
Don
On Tue, 2016-11-29 at 16:01 -0500, Don Zickus wrote:
> On Tue, Nov 29, 2016 at 11:56:03AM -0800, Brennan Ashton wrote:
> >
> > >
> > > >
> > > > SetDiscoveryFilter might also be necessary/helpful.
> > >
> > > Yep, the SetDiscoveryFilter might be the way to go, the only
> > > missing
> > > part that it doesn't do right now is to disable duplicate
> > > filtering,
> > > but we might need some flag with a big warning that this will
> > > spam
> > > the
> > > bus like crazy or perhaps it can only be used along RSSI
> > > filtering,
> > > which is to prevent people to use advertisement/scanning APIs as
> > > a
> > > transport over D-Bus.
> > >
> > > We could offer a file descriptor based solution for transport
> > > emulation using scanning/advertising to prevent spamming D-Bus
> > > but
> > > that has to play nicely with other application, either that or we
> > > only
> > > allow this over MGMT interface which is what we suggest in case
> > > there
> > > is no other use for Bluetooth in the system.
> > >
> > > And btw, I wouldn't account Android and other mobile OSes
> > > allowing
> > > such raw access for much longer, it takes way too much power and
> > > can
> > > probably block any other Bluetooth peripheral to work, so it is
> > > probably only good to write packet sniffer and other debug tools
> > > on
> > > top of the system but it really offer nothing to the regular
> > > user.
> >
> > I have had to resort to using the HCI interface to work with
> > scanning
> > and advertising beacon packets. I had mentioned in an earlier
> > thread
> > the issue with duplicates. Not only do you end up with a lot of
> > spam
> > on the dbus interface you end up with an ever increasing number of
> > bluetooth devices. The Bluetooth mesh uses this transport, so I
> > really
> > would like to see a nice interface to support rx/tx of these
> > packets.
>
> Hi,
>
> Sorry for being ignorant (as I can't quite find the filter duplicate
> code
> other than the setting of the bit), but would throttling work
> here? Cap the
> duplicates at say every 100ms or 10x/second. That probably won't
> help with
> power consumption (unless start/stop of the radio is quick?).
>
> Just trying to help move this along.. willing to code/test.
>
> Cheers,
> Don
>
The thread I mentioned is here:
https://marc.info/?t=147345134200002&r=1&w=2
The constant of interest is this LE_SCAN_FILTER_DUP_ENABLE. I had to
recompile with this disabled because I never wanted the filter for my
application. I had proposed making this an option in the adaptor
interface, but there did not seem to be any interest.
--Brennan
On Tue, Nov 29, 2016 at 11:56:03AM -0800, Brennan Ashton wrote:
> > > SetDiscoveryFilter might also be necessary/helpful.
> >
> > Yep, the SetDiscoveryFilter might be the way to go, the only missing
> > part that it doesn't do right now is to disable duplicate filtering,
> > but we might need some flag with a big warning that this will spam
> > the
> > bus like crazy or perhaps it can only be used along RSSI filtering,
> > which is to prevent people to use advertisement/scanning APIs as a
> > transport over D-Bus.
> >
> > We could offer a file descriptor based solution for transport
> > emulation using scanning/advertising to prevent spamming D-Bus but
> > that has to play nicely with other application, either that or we
> > only
> > allow this over MGMT interface which is what we suggest in case there
> > is no other use for Bluetooth in the system.
> >
> > And btw, I wouldn't account Android and other mobile OSes allowing
> > such raw access for much longer, it takes way too much power and can
> > probably block any other Bluetooth peripheral to work, so it is
> > probably only good to write packet sniffer and other debug tools on
> > top of the system but it really offer nothing to the regular user.
>
> I have had to resort to using the HCI interface to work with scanning
> and advertising beacon packets. I had mentioned in an earlier thread
> the issue with duplicates. Not only do you end up with a lot of spam
> on the dbus interface you end up with an ever increasing number of
> bluetooth devices. The Bluetooth mesh uses this transport, so I really
> would like to see a nice interface to support rx/tx of these packets.
Hi,
Sorry for being ignorant (as I can't quite find the filter duplicate code
other than the setting of the bit), but would throttling work here? Cap the
duplicates at say every 100ms or 10x/second. That probably won't help with
power consumption (unless start/stop of the radio is quick?).
Just trying to help move this along.. willing to code/test.
Cheers,
Don
On Tue, 2016-11-29 at 14:45 +0200, Luiz Augusto von Dentz wrote:
> Hi Barry, Don,
>
> On Tue, Nov 29, 2016 at 2:24 PM, Barry Byford <[email protected]>
> wrote:
> >
> > Hello Don,
> >
> >
> > On 28 November 2016 at 20:55, Don Zickus <[email protected]>
> > wrote:
> > >
> > > On Thu, Nov 24, 2016 at 03:07:21PM +0200, Luiz Augusto von Dentz
> > > wrote:
> > > >
> > > > Hi Don,
> > > >
> > > > On Wed, Nov 23, 2016 at 11:40 PM, Don Zickus <[email protected]
> > > > m> wrote:
> > > > >
> > > > > Hi,
> > > > >
> > > > > I was trying to write some code to continuously scan the
> > > > > bluetooth field
> > > > > for bluetooth devices sending advertising packets (ie beacon-
> > > > > mode).
> > > >
> > > > That is tricky, if you have anyone else trying to use the
> > > > adapter in
> > > > this situation it will probably be blocked, we may add support
> > > > for
> > > > setting intervals but that will probably be a best effort in
> > > > case
> > > > there is no connection or other usage of the adapter by the
> > > > system.
> > > >
> > > > >
> > > > > These devices would come and go so I wanted to avoid the
> > > > > cache.
> > > >
> > > > Beacon are not normally not connectable, connections and
> > > > continuous
> > > > advertisement don't go well together so we will probably have
> > > > to
> > > > reduce the intervals in order to maintain any traffic on the
> > > > connections.
> > >
> > >
> > > Hi Luiz,
> > >
> > > Thanks for the response. I am wondering if I explained it
> > > wrong. I wasn't
> > > looking to do advertisements but instead scan for
> > > advertisements. I also
> > > don't plan to connect to any of the advertising device, just read
> > > the
> > > advertised data.
> > >
> > >
> > > >
> > > >
> > > > >
> > > > > I noticed the D-Bus interface doesn't quite allow me to do
> > > > > this (as it
> > > > > caches the devices and I can't monitor the RSSI field). But
> > > > > I think the
> > > > > bluetooth management interface does. Is that the correct
> > > > > approach?
> > > >
> > > > Yep you could in theory use the MGMT interface and manually add
> > > > you
> > > > beacon management on top, but I guess you don't want
> > > > applications to
> > > > do that since it would require root permissions to connect to
> > > > the
> > > > management socket, so making bluetoothd, via kernel?, to adjust
> > > > the
> > > > intervals is probably a better idea in the long run. We would
> > > > probably
> > > > have to maintain the biggest advertising window possible, and
> > > > the
> > > > consider:
> > > >
> > > > 1. Is it connectable/there any advertising instance that is
> > > > connectable? If yes, the it has to adjust the window to allow
> > > > them
> > > > (perhaps using the default connection parameters).
> > > > 2. In case of a connection is made the controller may not be
> > > > able to
> > > > advertise anymore, and in case it can still advertise we need
> > > > to make
> > > > sure it doesn't interrupt the connection (this is not very
> > > > clear if
> > > > the controller is suppose to manage this somehow).
> > > > 3. Similar to the connection situation we may have application
> > > > scanning, again there might be problems if the controller
> > > > cannot scan
> > > > while advertising we would probably have to stop advertising.
> > >
> > > Hmm, as I said above, I am wondering if I explained it wrong.
> > >
> > > I was wondering how much was already done because in reality, I
> > > was just
> > > going to mimic what android does on the phones with apple
> > > ibeacons except my
> > > machines stay put and the ibeacons travel.
> > >
> > > Currently I was using 'hcitool lescan --duplicates' and 'hcidump'
> > > and trying
> > > to script that. But wanted to be smarter. :-)
> >
> > I am planning on doing a similar application as you describe and
> > understood that you should be able to do much of what you want with
> > the dbus API.
> > Have you taken a look at adapter/StartDiscovery?
> > It is documented at
> > git.kernel.org/cgit/bluetooth/bluez.git/tree/doc/adapter-
> > api.txt#n12
> > You would then monitor the PropertiesChanged signal on the system
> > dbus.
> >
> > SetDiscoveryFilter might also be necessary/helpful.
>
> Yep, the SetDiscoveryFilter might be the way to go, the only missing
> part that it doesn't do right now is to disable duplicate filtering,
> but we might need some flag with a big warning that this will spam
> the
> bus like crazy or perhaps it can only be used along RSSI filtering,
> which is to prevent people to use advertisement/scanning APIs as a
> transport over D-Bus.
>
> We could offer a file descriptor based solution for transport
> emulation using scanning/advertising to prevent spamming D-Bus but
> that has to play nicely with other application, either that or we
> only
> allow this over MGMT interface which is what we suggest in case there
> is no other use for Bluetooth in the system.
>
> And btw, I wouldn't account Android and other mobile OSes allowing
> such raw access for much longer, it takes way too much power and can
> probably block any other Bluetooth peripheral to work, so it is
> probably only good to write packet sniffer and other debug tools on
> top of the system but it really offer nothing to the regular user.
I have had to resort to using the HCI interface to work with scanning
and advertising beacon packets. I had mentioned in an earlier thread
the issue with duplicates. Not only do you end up with a lot of spam
on the dbus interface you end up with an ever increasing number of
bluetooth devices. The Bluetooth mesh uses this transport, so I really
would like to see a nice interface to support rx/tx of these packets.
Hi Barry, Don,
On Tue, Nov 29, 2016 at 2:24 PM, Barry Byford <[email protected]> wrote:
> Hello Don,
>
>
> On 28 November 2016 at 20:55, Don Zickus <[email protected]> wrote:
>> On Thu, Nov 24, 2016 at 03:07:21PM +0200, Luiz Augusto von Dentz wrote:
>>> Hi Don,
>>>
>>> On Wed, Nov 23, 2016 at 11:40 PM, Don Zickus <[email protected]> wrote:
>>> > Hi,
>>> >
>>> > I was trying to write some code to continuously scan the bluetooth field
>>> > for bluetooth devices sending advertising packets (ie beacon-mode).
>>>
>>> That is tricky, if you have anyone else trying to use the adapter in
>>> this situation it will probably be blocked, we may add support for
>>> setting intervals but that will probably be a best effort in case
>>> there is no connection or other usage of the adapter by the system.
>>>
>>> > These devices would come and go so I wanted to avoid the cache.
>>>
>>> Beacon are not normally not connectable, connections and continuous
>>> advertisement don't go well together so we will probably have to
>>> reduce the intervals in order to maintain any traffic on the
>>> connections.
>>
>>
>> Hi Luiz,
>>
>> Thanks for the response. I am wondering if I explained it wrong. I wasn't
>> looking to do advertisements but instead scan for advertisements. I also
>> don't plan to connect to any of the advertising device, just read the
>> advertised data.
>>
>>
>>>
>>> > I noticed the D-Bus interface doesn't quite allow me to do this (as it
>>> > caches the devices and I can't monitor the RSSI field). But I think the
>>> > bluetooth management interface does. Is that the correct approach?
>>>
>>> Yep you could in theory use the MGMT interface and manually add you
>>> beacon management on top, but I guess you don't want applications to
>>> do that since it would require root permissions to connect to the
>>> management socket, so making bluetoothd, via kernel?, to adjust the
>>> intervals is probably a better idea in the long run. We would probably
>>> have to maintain the biggest advertising window possible, and the
>>> consider:
>>>
>>> 1. Is it connectable/there any advertising instance that is
>>> connectable? If yes, the it has to adjust the window to allow them
>>> (perhaps using the default connection parameters).
>>> 2. In case of a connection is made the controller may not be able to
>>> advertise anymore, and in case it can still advertise we need to make
>>> sure it doesn't interrupt the connection (this is not very clear if
>>> the controller is suppose to manage this somehow).
>>> 3. Similar to the connection situation we may have application
>>> scanning, again there might be problems if the controller cannot scan
>>> while advertising we would probably have to stop advertising.
>>
>> Hmm, as I said above, I am wondering if I explained it wrong.
>>
>> I was wondering how much was already done because in reality, I was just
>> going to mimic what android does on the phones with apple ibeacons except my
>> machines stay put and the ibeacons travel.
>>
>> Currently I was using 'hcitool lescan --duplicates' and 'hcidump' and trying
>> to script that. But wanted to be smarter. :-)
>
> I am planning on doing a similar application as you describe and
> understood that you should be able to do much of what you want with
> the dbus API.
> Have you taken a look at adapter/StartDiscovery?
> It is documented at
> git.kernel.org/cgit/bluetooth/bluez.git/tree/doc/adapter-api.txt#n12
> You would then monitor the PropertiesChanged signal on the system dbus.
>
> SetDiscoveryFilter might also be necessary/helpful.
Yep, the SetDiscoveryFilter might be the way to go, the only missing
part that it doesn't do right now is to disable duplicate filtering,
but we might need some flag with a big warning that this will spam the
bus like crazy or perhaps it can only be used along RSSI filtering,
which is to prevent people to use advertisement/scanning APIs as a
transport over D-Bus.
We could offer a file descriptor based solution for transport
emulation using scanning/advertising to prevent spamming D-Bus but
that has to play nicely with other application, either that or we only
allow this over MGMT interface which is what we suggest in case there
is no other use for Bluetooth in the system.
And btw, I wouldn't account Android and other mobile OSes allowing
such raw access for much longer, it takes way too much power and can
probably block any other Bluetooth peripheral to work, so it is
probably only good to write packet sniffer and other debug tools on
top of the system but it really offer nothing to the regular user.
--
Luiz Augusto von Dentz
Hello Don,
On 28 November 2016 at 20:55, Don Zickus <[email protected]> wrote:
> On Thu, Nov 24, 2016 at 03:07:21PM +0200, Luiz Augusto von Dentz wrote:
>> Hi Don,
>>
>> On Wed, Nov 23, 2016 at 11:40 PM, Don Zickus <[email protected]> wrote:
>> > Hi,
>> >
>> > I was trying to write some code to continuously scan the bluetooth field
>> > for bluetooth devices sending advertising packets (ie beacon-mode).
>>
>> That is tricky, if you have anyone else trying to use the adapter in
>> this situation it will probably be blocked, we may add support for
>> setting intervals but that will probably be a best effort in case
>> there is no connection or other usage of the adapter by the system.
>>
>> > These devices would come and go so I wanted to avoid the cache.
>>
>> Beacon are not normally not connectable, connections and continuous
>> advertisement don't go well together so we will probably have to
>> reduce the intervals in order to maintain any traffic on the
>> connections.
>
>
> Hi Luiz,
>
> Thanks for the response. I am wondering if I explained it wrong. I wasn't
> looking to do advertisements but instead scan for advertisements. I also
> don't plan to connect to any of the advertising device, just read the
> advertised data.
>
>
>>
>> > I noticed the D-Bus interface doesn't quite allow me to do this (as it
>> > caches the devices and I can't monitor the RSSI field). But I think the
>> > bluetooth management interface does. Is that the correct approach?
>>
>> Yep you could in theory use the MGMT interface and manually add you
>> beacon management on top, but I guess you don't want applications to
>> do that since it would require root permissions to connect to the
>> management socket, so making bluetoothd, via kernel?, to adjust the
>> intervals is probably a better idea in the long run. We would probably
>> have to maintain the biggest advertising window possible, and the
>> consider:
>>
>> 1. Is it connectable/there any advertising instance that is
>> connectable? If yes, the it has to adjust the window to allow them
>> (perhaps using the default connection parameters).
>> 2. In case of a connection is made the controller may not be able to
>> advertise anymore, and in case it can still advertise we need to make
>> sure it doesn't interrupt the connection (this is not very clear if
>> the controller is suppose to manage this somehow).
>> 3. Similar to the connection situation we may have application
>> scanning, again there might be problems if the controller cannot scan
>> while advertising we would probably have to stop advertising.
>
> Hmm, as I said above, I am wondering if I explained it wrong.
>
> I was wondering how much was already done because in reality, I was just
> going to mimic what android does on the phones with apple ibeacons except my
> machines stay put and the ibeacons travel.
>
> Currently I was using 'hcitool lescan --duplicates' and 'hcidump' and trying
> to script that. But wanted to be smarter. :-)
I am planning on doing a similar application as you describe and
understood that you should be able to do much of what you want with
the dbus API.
Have you taken a look at adapter/StartDiscovery?
It is documented at
git.kernel.org/cgit/bluetooth/bluez.git/tree/doc/adapter-api.txt#n12
You would then monitor the PropertiesChanged signal on the system dbus.
SetDiscoveryFilter might also be necessary/helpful.
Regards,
Barry
>
> Cheers,
> Don
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Nov 24, 2016 at 03:07:21PM +0200, Luiz Augusto von Dentz wrote:
> Hi Don,
>
> On Wed, Nov 23, 2016 at 11:40 PM, Don Zickus <[email protected]> wrote:
> > Hi,
> >
> > I was trying to write some code to continuously scan the bluetooth field
> > for bluetooth devices sending advertising packets (ie beacon-mode).
>
> That is tricky, if you have anyone else trying to use the adapter in
> this situation it will probably be blocked, we may add support for
> setting intervals but that will probably be a best effort in case
> there is no connection or other usage of the adapter by the system.
>
> > These devices would come and go so I wanted to avoid the cache.
>
> Beacon are not normally not connectable, connections and continuous
> advertisement don't go well together so we will probably have to
> reduce the intervals in order to maintain any traffic on the
> connections.
Hi Luiz,
Thanks for the response. I am wondering if I explained it wrong. I wasn't
looking to do advertisements but instead scan for advertisements. I also
don't plan to connect to any of the advertising device, just read the
advertised data.
>
> > I noticed the D-Bus interface doesn't quite allow me to do this (as it
> > caches the devices and I can't monitor the RSSI field). But I think the
> > bluetooth management interface does. Is that the correct approach?
>
> Yep you could in theory use the MGMT interface and manually add you
> beacon management on top, but I guess you don't want applications to
> do that since it would require root permissions to connect to the
> management socket, so making bluetoothd, via kernel?, to adjust the
> intervals is probably a better idea in the long run. We would probably
> have to maintain the biggest advertising window possible, and the
> consider:
>
> 1. Is it connectable/there any advertising instance that is
> connectable? If yes, the it has to adjust the window to allow them
> (perhaps using the default connection parameters).
> 2. In case of a connection is made the controller may not be able to
> advertise anymore, and in case it can still advertise we need to make
> sure it doesn't interrupt the connection (this is not very clear if
> the controller is suppose to manage this somehow).
> 3. Similar to the connection situation we may have application
> scanning, again there might be problems if the controller cannot scan
> while advertising we would probably have to stop advertising.
Hmm, as I said above, I am wondering if I explained it wrong.
I was wondering how much was already done because in reality, I was just
going to mimic what android does on the phones with apple ibeacons except my
machines stay put and the ibeacons travel.
Currently I was using 'hcitool lescan --duplicates' and 'hcidump' and trying
to script that. But wanted to be smarter. :-)
Cheers,
Don
Hi Don,
On Wed, Nov 23, 2016 at 11:40 PM, Don Zickus <[email protected]> wrote:
> Hi,
>
> I was trying to write some code to continuously scan the bluetooth field
> for bluetooth devices sending advertising packets (ie beacon-mode).
That is tricky, if you have anyone else trying to use the adapter in
this situation it will probably be blocked, we may add support for
setting intervals but that will probably be a best effort in case
there is no connection or other usage of the adapter by the system.
> These devices would come and go so I wanted to avoid the cache.
Beacon are not normally not connectable, connections and continuous
advertisement don't go well together so we will probably have to
reduce the intervals in order to maintain any traffic on the
connections.
> I noticed the D-Bus interface doesn't quite allow me to do this (as it
> caches the devices and I can't monitor the RSSI field). But I think the
> bluetooth management interface does. Is that the correct approach?
Yep you could in theory use the MGMT interface and manually add you
beacon management on top, but I guess you don't want applications to
do that since it would require root permissions to connect to the
management socket, so making bluetoothd, via kernel?, to adjust the
intervals is probably a better idea in the long run. We would probably
have to maintain the biggest advertising window possible, and the
consider:
1. Is it connectable/there any advertising instance that is
connectable? If yes, the it has to adjust the window to allow them
(perhaps using the default connection parameters).
2. In case of a connection is made the controller may not be able to
advertise anymore, and in case it can still advertise we need to make
sure it doesn't interrupt the connection (this is not very clear if
the controller is suppose to manage this somehow).
3. Similar to the connection situation we may have application
scanning, again there might be problems if the controller cannot scan
while advertising we would probably have to stop advertising.
--
Luiz Augusto von Dentz