On Fri, Oct 16, 2026 at 3:49 PM chao an <[email protected]> wrote:
> So the real reason you've been objecting to my proposal is that your team > has been working on something similar, correct? > > If you can give me a clear timeline for when your implementation will be > submitted upstream, I'm happy to withdraw my PR and let your code serve as > the baseline. I'm not here to fight over ownership of the Bluetooth stack. > My only motivation is that NuttX's lack of a capable Bluetooth stack is > driving every developer toward Zephyr — and as a PMC member, I think you > should be asking yourselves why this gap has remained unfilled for so long. > > I object to landing the whole bluetooth stack into kernel space directly either yours and ours . This is the same feeling from raiden00pl too, let's see other people's opinions here. But it's fine for me to host the whole code in nuttx-apps.git and refactor components to kernel space step by step. > As for the current PR, I'll remove the shell components from the stack and > move them into apps/ where they belong. The base profiles (A2DP, BLE) will > stay in libc — The architecture is wrong to host any bluetooth profile in libc. in flat build mode this gives a significant performance > boost to the overall stack, which is the primary deployment model for most > NuttX devices. > > Performance should remain the same whether the base profile is hosted in libc or apps, could you point out any technical reason which impacts the performance in the flat mode? > A few additional data points regarding our timeline: our product is > scheduled for release in December, and Bluetooth SIG certification is > already in progress — we expect to receive it around November. If the > baseline were to switch to your team's stack with its different > architecture, that certification cycle would need to be repeated, which is > not trivial given the time and cost involved. > > Xiang Xiao <[email protected]> 于2026年10月16日周五 15:08写道： > > > On Fri, Oct 16, 2026 at 2:44 PM chao an <[email protected]> wrote: > > > > > Hi raiden00pl, > > > > > > Regarding your point about the NimBLE port using the POSIX API — yes, > it > > > uses POSIX, but there are real issues with the current implementation > > that > > > go beyond just kernel/protected mode support. > > > 1. ble_npl_hw_enter_critical is not a real critical section > > > > > > Look at the NuttX port's implementation: > > > > > > > > > https://github.com/apache/mynewt-nimble/blob/master/porting/npl/nuttx/src/os_atomic.c > > > > > > static pthread_mutex_t s_mutex = > PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; > > > > > > uint32_t ble_npl_hw_enter_critical(void) > > > { > > > pthread_mutex_lock(&s_mutex); > > > return 0; > > > } > > > > > > This is a mutex, not a critical section. It does not disable interrupts > > or > > > preemption — an ISR can still fire and corrupt data that the "critical > > > section" was supposed to protect. On top of that, using a mutex opens > the > > > door to ABBA deadlocks when combined with any other lock held inside > the > > > critical region: > > > > > > - Thread A: enter_critical → lock(s_mutex) → try lock(mutex M) ← > > blocked > > > by B > > > - Thread B: lock(M) → enter_critical → lock(s_mutex) ← blocked by A > > > > > > Compare this with the FreeRTOS port, which correctly uses > > > vPortEnterCritical() / vPortExitCritical() (i.e., actually disabling > > > scheduling/preemption). The current NuttX port simply does not meet the > > > semantic contract that the NimBLE stack expects from > > > ble_npl_hw_enter_critical. > > > 2. Time subsystem uses clock_gettime instead of kernel tick APIs > > > > > > > > > > > > https://github.com/apache/mynewt-nimble/blob/master/porting/npl/nuttx/src/os_time.c > > > > > > ble_npl_time_get() is backed by clock_gettime(CLOCK_MONOTONIC, ...), > > which > > > involves a syscall and floating-point arithmetic on every call. In a > BLE > > > stack where timestamps and timing are on the hot path, this adds > > measurable > > > overhead compared to accessing the kernel tick counter directly. > > > 3. Others are already using the kernel approach — and for good reason > > > > > > A concrete example: Xiaomi's Bluetooth stack (zblue) for openvela/NuttX > > > uses kernel APIs directly, bypassing POSIX for the performance-critical > > > paths: > > > > https://github.com/sprhawk/zblue-port-openvela/tree/yaotepai/port/kernel > > > > > > This isn't an academic exercise — it's a production choice. They > > recognized > > > that a BLE stack needs tight integration with the OS timer subsystem, > > > direct access to critical section primitives, and efficient event > > delivery, > > > none of which POSIX provides well in this context. > > > My question > > > > > > If other organizations are already using a more performant, > > architecturally > > > correct kernel-level integration for their BLE stacks on NuttX, why > > should > > > we be told that we must use the slower, less correct POSIX path? > NuttX's > > > POSIX compliance is valuable, but it shouldn't come at the cost of > > shipping > > > a BLE stack with a broken critical section primitive. There should be > > room > > > for both approaches, and the decision should be driven by technical > > merit, > > > not by treating POSIX as the only acceptable answer. > > > > > > > > I don't object to moving the key bluetooth stack to kernel space like how > > the current bluetooth stack is done, > > what I object to is that the current state of > > https://github.com/apache/nuttx/pull/20686 is far to move entirely > > into kernel space. > > If I low my quality bar, I have requested my teammate to upstream our > > implementation: > > https://github.com/sprhawk/zblue-port-openvela/tree/yaotepai/port/kernel > > since much work needs to be done before it can achieve the quality > > upstream. > > BTW, many zephyr class BT features are developed by my team and upstream > to > > Zeprhy community. > > If considering the quality, our version is much better since: > > > > 1. Product on smart speaker last year > > 2. Pass Bluetooth SIG BT/BLE 6.2 certification at 2026.06 > > 3. Product on wear device by end of this year > > >
