Mares Smart Dive Computer + Bluelink pro

[Linus Torvalds]

On Wed, Sep 26, 2018 at 2:14 PM Linus Torvalds
<torvalds at linux-foundation.org> wrote:
>
> So I don't see why that data read seemed to fail and not return any
> information. Everything else looked really good, and the Mares app
> seems to use the exact same command set, just slightly different
> offset/length values.

Well, my BlueLink arrived, and I have two observations:

 - this is the *slowest* BLE thing I've ever seen in my life.

I think it's a bad interaction with how Qt does Bluez, because I'm
assuming that it works much better on Android, where all the BLE GATT
information is cached (I think). With Bluez, Qt ends up doing the full
discovery by actually talking to the thing over BLE every time, and it
normally takes up to a few tens of seconds to get all the GATT
information.

With the BlueLink, I had to up the BLE timeout for waiting for service
discovery, because it took closer to a minute. Whee.

 - I see the same behavior Fabio sees.

I can see it communicate fine, but it doesn't actually reply with the
serial number data, it just returns EOF immediately.

I guess that counts as "good news". Although this thing is so slow
that it feels like it's almost faster to just debug it over email with
Fabio, than to play with it locally here ;)

I will see if it works if I ask for the 16 bytes at offset zero instead..

                   Linus