set response=True for write_gatt_char to fix silent failure

[tensorturtle]

I was testing FTMS on my Elite Suito T smart trainer and the resistance wasn't changing using the example script.

I found that setting response=True for bleak's write_gatt_char fixed it.

Huawei docs says "When the phone request the control of a fitness machine, the fitness machine needs to respond with 0x80...". I'm guessing 'needs' here means that the request itself needs to be a "Write with response" type.

I'm not sure why it worked before when response=False.

[zacharyedwardbull]

Hi @tensorturtle, thanks for sending this. Just to check, does the setting resistance part not work for any turbo trainers at the moment? Or just the Elite Suito T? And did it work before?

Cheers

[tensorturtle]

I only have the Elite Suito T available to test so I'm sorry I can't offer any info about other trainers. It worked before according to my memory plus I wouldn't have made the initial PR if it wasn't successful.

[zacharyedwardbull]

Has anything changed on your side since you implemented it? Are you using a different operating system? I'm happy to merge this but just want to understand why it wasn't an issue before.

[tensorturtle]

There is a possibility that I set it to False before submitting the PR as a way to reduce the visual clutter, since the example prints the responses after every single message which can be a bit overwhelming. I didn't think at the time that this option would affect functionality at all.

[zacharyedwardbull]

It looks like the behaviour of bleak write_gatt_char may have changed somewhat, although not sure if it is related here e.g: hbldh/bleak#909.

Would you be able to try using the older version of bleak that would have been around when you first wrote the code? See if the current code (before your PR) works then.

Once we know why it worked before and not now I will merge in the update.

[tensorturtle]

@zacharyedwardbull Your prediction was absolutely correct. Thank you for looking it up.

The breaking change in bleak was introduced in bleak==0.21

Bleak Version	response=False	response=True	Empty
0.21.1 (latest)	Fails	Works	Works
0.20.2 (before breaking change)	Works	Works	Works

[zacharyedwardbull]

Thanks for checking, nice work! Merged it.