OSTC over BLE experiences and questions

Dirk Hohndel dirk at hohndel.org
Wed Jul 5 19:07:52 PDT 2017


I wonder... Is this actually be counting and using an 8 bit register that overflows? So writing 255 actually would reduce the number of credits? Have you tried asking for, say 100, count, and then ask for the next 100 when you are out of credits based on your count?

/D

⁣-- 
>From my phone​


-------- Original Message --------
From: Jan Mulder <jlmulder at xs4all.nl>
Sent: Wed Jul 05 11:01:25 PDT 2017
To: Linus Torvalds <torvalds at linux-foundation.org>, Matthias Heinrichs <matthias.heinrichs at heinrichsweikamp.com>
Cc: Dirk Hohndel <dirk at hohndel.org>, Subsurface Mailing List <subsurface at subsurface-divelog.org>
Subject: Re: OSTC over BLE experiences and questions

On 05-07-17 18:23, Linus Torvalds wrote:
> On Wed, Jul 5, 2017 at 8:57 AM, Matthias Heinrichs
> <matthias.heinrichs at heinrichsweikamp.com> wrote:
>>
>> Theoretically, this should happen through the flow control lines from the
>> Bluetooth Chipset to our applications processor. When using BLE (Due to the
>> much lower end-to-end baud rate), the flow control already is very active
>> and controlling the bytes from the OSTC to the Bluetooth chipset. When
>> looking at the snoop file, it shouldn't hurt to reset this credit counter
>> from time to time to 255. Or try a higher number like 65536? Specification
>> says 255 but have you tried higher values?
> 
> It says it's only a single byte, so 255 is the max..
> 
>                   Linus
> 

I made some progress by sending new credits, but it seems a bit more 
complex that just sending a new 255 credits from time to time, but I'm 
sure it going to work. I already had about 800 packets incoming during 
my testing, but things seems very fragile. So too much WIP to push 
anything out.

This all said, I really appreciate that you (Matthias and Linus) give 
input to this subject.

--jan
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