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Is there any way to get an official Firmware Image with a BT Kernel Patch:
We are having the same issue like the thread:

If a BT Device has a long advertising interval BLUEZ is not able to connect due to a short timeout.

What needs to be changes is:
#define HCI_LE_AUTOCONN_TIMEOUT msecs_to_jiffies(20000)

It is 4000 in the Linux Kernel and we need at least 15000.
Can be done in:

But as it is a Kernel change there is not much we can do inside the container...

Any advice or posibility to get such a fix?

We have a customer behind that would like to use netPI.
Well right now I do not see that we can provide such a special kernel patch meeting for your requirements.

For netPI we use a stable kernel 4.9 since 2017. In this kernel I see the value of 2000 set in the hci.h file.

Meanwhile I see a value 4000 in the kernel 4.19 (current supported on by the Raspberry Foundation), so somebody must have changed it.

A value 20000 would be 10 times more than used today and I feel this is out of scope what we can decide on/provide without side effects for other users.

We are proud of keeping the netPI system software stable now for 7 month and I want to keep it as long as possible stable. I think you understand my position in the name of the community.

The only chance I see for you is to use your own SD card within netPI using Raspbian OS were a patch can be applied according to your spec yourself. Sorry for having no better news for you.

You never fail until you stop trying.“, Albert Einstein (1879 - 1955)

I see the point but many people complain about this especially when the have low power devices using long advertising intervalls.

A custom build is not a solution for us as we are looking for something that is production scalable.

Any chance to get a special branch for our customer? We can talk about details in PM.
Well I just can tell you that Hilscher always uses official Linux distributions for all our builds. This is our experience how to be always compatible with 99.99% of all Linux use cases.

And as you said "so many people really complain about this timeout" then we should see official changes in Linux, don't you agree? I also looked to kernel 5.x and not even there I see changes.

We have never build branches for netPI software so far and have not the intension to leave this path. Else we have to maintain it for example when we gonna update to kernel 4.19. Supposing we would have other requests like this also pending, then the effort would be infinite to track all the changes.
You never fail until you stop trying.“, Albert Einstein (1879 - 1955)

Well I read in the Bluetooth 4.1 core specification that the advertising interval should be between 20msec and 10.24secs.

Don't know why one has set it now to 4 seconds, but is in the limits.

22seconds is definitively out of the limit and I really can't estimate the impact and influence on the overall behaviour of the BT stack and scanning procedure for others if it would be changed. So in no way this would become standard with netPI.
You never fail until you stop trying.“, Albert Einstein (1879 - 1955)


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