advertising max/min interval being ignored

[potto216]

I'm seeing the same problem as issue #21. I'm running on Debian and with Blue Z 5.74

/usr/libexec/bluetooth/bluetoothd -v
5.74

And experimental features (although the same issue happens without them)

/usr/libexec/bluetooth/bluetoothd -E -d

And when I advertise using the program https://github.com/potto216/bluer-cmd/blob/main/le_advertise/src/main.rs with the command line

cargo run --  --advertisement-type "broadcast" -u 123e4567-e89b-12d3-a456-426614174000 --interval 600,900 -v

I see the advertisement has the min/max interval between 600 msec and 900 msec

Advertisement { advertisement_type: Broadcast, service_uuids: {123e4567-e89b-12d3-a456-426614174000}, manufacturer_data: {}, solicit_uuids: {}, service_data: {}, advertising_data: {}, discoverable: Some(false), discoverable_timeout: None, system_includes: {}, local_name: None, appearance: None, duration: None, timeout: None, secondary_channel: None, min_interval: Some(600ms), max_interval: Some(900ms), tx_power: None, _non_exhaustive: () }

But the HCI with btmon shows it is being ignored

       Scan response length: 0
< HCI Command: LE Set Extended Advertising Parame.. (0x08|0x0036) plen 25  #51 [hci0] 124.779416
        Handle: 0x01
        Properties: 0x0010
          Use legacy advertising PDUs: ADV_NONCONN_IND
        Min advertising interval: 1280.000 msec (0x0800)
        Max advertising interval: 1280.000 msec (0x0800)
        Channel map: 37, 38, 39 (0x07)
        Own address type: Random (0x01)
        Peer address type: Public (0x00)
        Peer address: 00:00:00:00:00:00 (OUI 00-00-00)
        Filter policy: Allow Scan Request from Any, Allow Connect Request from Any (0x00)
        TX power: Host has no preference (0x7f)
        Primary PHY: LE 1M (0x01)
        Secondary max skip: 0x00
        Secondary PHY: LE 1M (0x01)
        SID: 0x00
        Scan request notifications: Disabled (0x00)

and over the air captures show the advertisement is being ignored.

@surban Would looking at the d-bus messages be the next step?

[surban]

@surban Would looking at the d-bus messages be the next step?

Yes, and if they seem to be correct it would help to see what is going on in bluetoothd.

[potto216]

I see the same behavior with bluetoothctl ignoring the advertisement min/max interval values. Attached are two files. The first advertising_interval_fail_bluetoothctl.txt has the output running and monitoring bluetoothctl. The second advertising_interval_fail_bluer.txt is running and monitoring the le advertising program using Bluer. Both output files are composed of the program output, the btmon output and the dbus output. To capture the dbus output I used

sudo dbus-monitor --system "type='signal',sender='org.bluez'"  

Because these showed nothing when running the programs

sudo dbus-monitor --system "type='signal',destination='org.bluez'" 
sudo dbus-monitor --system "type='signal',destination='org.bluez',sender='org.bluez'"

I looked for the dbus org.bluez.LEAdvertisement because it has advertising interval setting uint32 MinInterval [Experimental] and uint32 MaxInterval [Experimental].

When looking at both output, I saw the HCI command with the default min max interval parms:

< HCI Command: LE Set Extended Advertising Paramet.. (0x08|0x0036) plen 25  #1 [hci0] 44.213445
        Handle: 0x01
        Properties: 0x0013
          Connectable
          Scannable
          Use legacy advertising PDUs: ADV_IND
        Min advertising interval: 1280.000 msec (0x0800)
        Max advertising interval: 1280.000 msec (0x0800)
        Channel map: 37, 38, 39 (0x07)
        Own address type: Public (0x00)
        Peer address type: Public (0x00)
        Peer address: 00:00:00:00:00:00 (OUI 00-00-00)
        Filter policy: Allow Scan Request from Any, Allow Connect Request from Any (0x00)
        TX power: Host has no preference (0x7f)
        Primary PHY: LE 1M (0x01)
        Secondary max skip: 0x00
        Secondary PHY: LE 1M (0x01)
        SID: 0x00
        Scan request notifications: Disabled (0x00)

And the dbus message for bluetoothctl of

string "type='signal',sender=':1.119',path='/org/bluez/advertising',interface='org.freedesktop.DBus.Properties',member='PropertiesChanged',arg0='org.bluez.LEAdvertisement1'"
# and
method call time=1714311596.212997 sender=:1.106 -> destination=:1.119 serial=181 path=/org/bluez/advertising; interface=org.freedesktop.DBus.Properties; member=GetAll
   string "org.bluez.LEAdvertisement1"

and for bluer program of

string "type='signal',sender=':1.116',path='/org/bluez/bluer/advertising/b0191643d3f3434eae417bfce7019e12',interface='org.freedesktop.DBus.Properties',member='PropertiesChanged',arg0='org.bluez.LEAdvertisement1'"
method call time=1714311418.842087 sender=:1.106 -> destination=org.freedesktop.DBus serial=143 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=StartServiceByName
   string ":1.116"
   uint32 0
method call time=1714311418.842484 sender=:1.106 -> destination=:1.116 serial=144 path=/org/bluez/bluer/advertising/b0191643d3f3434eae417bfce7019e12; interface=org.freedesktop.DBus.ObjectManager; member=GetManagedObjects
method call time=1714311418.843584 sender=:1.106 -> destination=:1.116 serial=145 path=/org/bluez/bluer/advertising/b0191643d3f3434eae417bfce7019e12; interface=org.freedesktop.DBus.Properties; member=GetAll
   string "org.bluez.LEAdvertisement1"
signal time=1714311418.854776 sender=:1.106 -> destination=(null destination) serial=146 path=/org/bluez/hci0; interface=org.freedesktop.DBus.Properties; member=PropertiesChanged
   string "org.bluez.LEAdvertisingManager1"
   array [
      dict entry(
         string "SupportedInstances"
         variant             byte 5
      )
      dict entry(
         string "ActiveInstances"
         variant             byte 1
      )
   ]
   array [
   ]

method call time=1714311431.767501 sender=:1.106 -> destination=org.freedesktop.DBus serial=151 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=RemoveMatch
   string "type='signal',sender=':1.116',path='/org/bluez/bluer/advertising/b0191643d3f3434eae417bfce7019e12',interface='org.freedesktop.DBus.Properties',member='PropertiesChanged',arg0='org.bluez.LEAdvertisement1'"

It looks to me that that the min/max intervals are never sent so the defaults are used (but I'm not very familiar with dbus messages). However, I see in the bluer code in Advertisement function register_interface that they are sent.

@surban do you think this is enough evidence of a bluez issue to file an issue with them?

[surban]

@surban do you think this is enough evidence of a bluez issue to file an issue with them?

Yes, seems to be a bluetoothd bug.

[potto216]

I added the issue https://github.com/bluez/bluez/issues/833