Embedded Working Group Meeting 2023-10-10

• Coordination Repository
• Meetings: Tuesday 8pm Europe/Berlin time
• Join the Chat
• Today's date: 2023-10-10
• Nominated issues
• IRC logs

Attendance

Write your GH username or Matrix handle here!

• adamgreig
• dirbaio
• newAM
• posborne
• cr1901
• mabez

Agenda

• Announcements
  • probe-rs 0.21.0 released
• Anti-spam bot issue check
• Rust target maintainers
  • Issue tracked in https://github.com/rust-embedded/wg/issues/704
• Mutex-trait
  • https://github.com/rust-embedded/mutex-trait/issues/13
  • no further discussion this week, should still decide if we want to continue promoting this trait
• book: tooling page needs updating
• bors: ops docs needs updating
• cortex-m volatile-register: still no update on PR
  • Perhaps just vendor our own volatileregister for now? it's only a few lines of code
  • unfortunately this is a breaking change and we don't want to release cortex-m 0.8 with just this
    • in part because all the PACs depend on cortex-m so it wrecks the ecosystem
    • perhaps we can have cortex-m-nr with just the InterruptNumber crate for PACs to use
  • plan:
    • make new cortex-m-interrupt-number crate with just the trait
    • have new cortex-m 0.7.8 re-export that trait
    • update svd2rust to use new crate directly instead of through cortex-m
    • now we can make new breaking cortex-m changes without all pacs needing updating
    • and thus also fix issues like this
    • perhaps also make PACs not depend on c-m-rt and just export the interrupt enum,
      with end users using the c-m-rt macro directly
• move heapless to r-e-c? can someone ask @japaric to transfer the repo?
  • https://github.com/japaric/heapless/issues/382

Last Week's Minutes

• Announcements
  • @MabezDev joins the risc-v and HAL teams
    Image Not Showing Possible Reasons

    • The image file may be corrupted
    • The server hosting the image is unavailable
    • The image path is incorrect
    • The image format is not supported

    Learn More →
  • embedded-io{,-async,-adaptors} 0.6 released with change to write_all
  • svdtools 0.3.3 released
  • svd2rust 0.30.1 released
  • rust 1.73 out Thurs
  • Ferrocene announcement/launch party tomorrow (link)
• Anti-spam bot still being tested, any issues?
• Should mutex-trait be archived/deprecated?
  • https://github.com/rust-embedded/mutex-trait/issues/13
  • Lots of discussion on this point. It's not clear if the current trait is serving a useful purpose and it's definitely not been widely adopted, but should we aim to fix it or just deprecate it?
  • Original RFC was https://github.com/rust-embedded/wg/blob/master/rfcs/0377-mutex-trait.md
  • The intended users are application, driver, HAL developers who want to abstract over a generic mutex to share state with interrupts/threads/etc
  • In practise, such an ecosystem hasn't developed, probably because the mutex interface (especially whether it requires &mut self or not) depends on the executor and what tradeoffs are desired
  • Additionally, the newer critical_section::Mutex is a concrete type which can have multiple backing providers per platform, so may be good enough for many use cases
  • We'll finish discussions on the issue
• book: tooling page still needs updating
• bors: ops documentation still needs updating
• rustc target maintainers:
  • @adamgreig to open wg issue to discuss WG teams being target maintainers
• volatile_register potentially unsound https://github.com/rust-embedded/cortex-m/issues/485
  • No update on volatile-register PR