On Tue, Dec 10, 2024 at 5:53 AM Nathan Hartman <hartman.nat...@gmail.com> wrote:
> Hi all, > > Unfortunately I missed the PR before it was merged, but PR-15073 has > broken High Priority, Zero Latency Interrupts! Fortunately I caught it > now. It was merged 17 hours ago. > > Zero Latency Interrupts doesn't remove from PR-15073. > This PR removed a very important Kconfig: config ARMV7M_USEBASEPRI, > and much of the logic related to it. This config is *required* when > using CONFIG_ARCH_HIPRI_INTERRUPT. > > PR-15073 doesn't remove ARMV7M_USEBASEPRI, but makes it enabled unconditionally, that's why this patch removes this config. > High Priority, Zero Latency Interrupts are documented here: > https://nuttx.apache.org/docs/latest/guides/zerolatencyinterrupts.html > > https://github.com/apache/nuttx/pull/15102 removes ARMV7M_USEBASEPRI from documentation to match the new code base. > I depend strongly on Zero Latency Interrupts. It is *required* for > critical handling in my firmware. I cannot use NuttX at all if NuttX > does not have Zero Latency Interrupts anymore. > > PR-15073 was meant to fix a regression in PR-14881. PR-14881 attempted > to optimize handling of g_current_regs. The commit log of PR-15073 > explains this. [1] > > We have to find another way to fix it, without destroying the Zero > Latency Interrupts feature. Otherwise, it is a very serious problem. > > I suggest to revert PR-15073, and possibly revert PR-14881, and find > another way to implement PR-14881 that doesn't cause this problem. > > References: > > [1] PR-15073: > https://github.com/apache/nuttx/commit/0e1b432dd068880d353ae91c01e610f85b4a16ea#diff-24754055e0d9f2d702b8503e7f5b520394cb59affb5d24457fe0641c1d7678ceL27 > > [2] PR-14881: https://github.com/apache/nuttx/pull/14881 > > [3] High Priority Zero Latency Interrupts: > https://nuttx.apache.org/docs/latest/guides/zerolatencyinterrupts.html > > Thanks, > Nathan >
