Hi Luiz On Tue, 22 Mar 2022 at 00:44, Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> wrote: > > Hi Adam, > > On Mon, Mar 21, 2022 at 4:03 PM Adam Pigg <adam@xxxxxxxxxxx> wrote: > > > > Hi > > > > A bit of background, I write a linux desktop/mobile app called > > Amazfish which interfaces with several watches over BLE using their > > GATT services. To do this, I use the bluez dbus api (technically a > > thin wrapper around it I wrote called qble > > https://github.com/piggz/qble) > > > > All has been good so far, I support several generations of > > Huami/Amazfit watches, as well as the open source Pinetime and > > Bangle.js. For the Amazfit watches, i have implementations for older > > devies such as the Bip, and newer ones such as the GTS. > > > > Much of the reverse engineering comes from the Android Gadget Bridge > > project, which supports many more devices. > > > > My community of users donated to buy me a newer device called a GTR2, > > which, according to the GB devs uses the same protocol as the slightly > > older GTS, and the packet captures I have from Android would support > > this. > > > > But this is where my trouble starts with Bluez, my existing > > implementation doesnt work at all. Normally, after a connection, I > > would wait for the ServicesResolved signal, which happens pretty fast > > on all other devices, but on the GTR2, it takes about 30 seconds, by > > which time, the watch has disconnected. (i get a disconnected signal > > immediately after the ServicesResolved signal) > > > > To rule out my code, I have tried several things: > > Gatttool > > With gattool, i can connect, get the services, enable a notification, > > write a value and get the expected results seemingly fine > > > > Python-gatt (using the bluez dbus api) > > Im unable to iterate the services, like my app, it takes 30 seconds to > > get the signal and then swiftly disconnects > > > > Gattlib (https://github.com/labapart/gattlib) > > Gattlib is interesting as it appears to have "borrowed" much of its > > code directly from bluez. When built against the system bluez, if the > > version is > 5.42, it will use the dbus api. When I do this, again im > > unable to list services on the watch. However, if I edit the build to > > force it to use its internal gatt implementation, which appears to be > > the same one used by gatttool, then, it IS able to interrogate the > > watch. > > > > I have attached 3 files > > 1. test python program which should print services, and associated btmon > > 2. btmon output while using gatttool > > 3. btmon output running gattlib discover example > > > > Note, other than discovery, I havnt been able to get gattlib to > > read/write/notify! > > > > It seems as though I may be triggering a bug in the bluez dbus api? > > Can anyone suggest anything? > > What version are you using? I would first try with the latest to see > if that something already fixed. > > Im using 5.63 already, which is the latest tag (on opensuse tumbleweed) I'll also try bluetoothctl and attach logs using that, though I suspect it will behave the same as the python library and my own library. > -- > Luiz Augusto von Dentz
