Proposal: Optional Configuration for UART TX Context in BLE H4 Driver

[VinitMehta7492]

Hi all,

I’d like to initiate a discussion regarding the current design of the BLE H4 driver in Zephyr, specifically around how UART TX is handled.

From what I understand, the H4 driver is optimized for BLE transactions and currently uses the ISR context for UART transmission. This design choice makes sense from a performance standpoint. However, in certain scenarios—such as multiprotocol (For E.g. Wi-Fi + BT) use cases—we’ve observed throughput degradation on Wi-Fi, which seems to be attributed to the ISR-based TX handling.

It appears that the current implementation does not account for such specific use cases, and I believe it would be beneficial to introduce an optional configuration that allows vendors to choose the context (ISR or thread) for UART TX based on their application needs.

Would the community be open to discussing the feasibility of such a configuration and incorporate it?

Looking forward to your thoughts and feedback.

Regards,
Vinit