Some code assumes that a critical-section impl is available #657
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This could be worked around by making the example explicitly require the feature to be enabled: The down side is that one would still need to pass it to the command line. At least it makes the error caught earlier and leaves a much less cryptic error message. |
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For the examples, that's exactly what I did in jannic@3d17af0 (I will send a PR once the PAC update is released) However it doesn't help users who write their own firmware based on rp2040-hal without using a BSP. They still need to remember to activate |
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We can probably do something similar to what IIRC defmt does with a symbol in linker file that's attempted to be linked if there's something missing. |
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I had the following idea, which unfortunately didn't work:
So why didn't this work? Well, besides defining the two symbols, one also needs to tell But we also can't just set the feature flag, because that may collide with a custom impl which needs a different restore state. |
Checking out rp-hal and attempting to build pio_audio.rs from the examples directory yields error:
rust-lld: error: undefined symbol: _critical_section_1_0_acquire
>>> referenced by pio_audio.db0b02402204ccb1-cgu.1
I found rp-rs/rp-hal#657 and discovered that enabling the required feature enables compilation.
Checking out rp-hal and attempting to build pio_audio.rs from the examples directory yields error:
rust-lld: error: undefined symbol: _critical_section_1_0_acquire
>>> referenced by pio_audio.db0b02402204ccb1-cgu.1
I found rp-rs/rp-hal#657 and discovered that enabling the required feature enables compilation.
While
critical-sectionis a non-optional dependency ofrp2040-hal, it's not sufficient to make critical sections work: There also needs to be an implementation of critical sections, which can be provided by activating the non-default featurecritical-section-impl.We don't want to make it a default feature, because users might want to provide their own implementation, and disabling a default feature of a crate that might be a transitive dependency of several other crates in the dependency tree is difficult.
But if it is not enabled, and some code uses a critical section, compilation fails with an ugly error message:
From this error message, it's not obvious how to solve the issue.
This is mitigated a bit by the fact that we do activate
critical-section-implfrom the BSP crates. (See #444 for details.)Still, it would be nice if we could improve that error message, avoid the situation altogether, or at least describe the requirement to activate
critical-section-impl(or provide an alternative implementation) in the docs.The text was updated successfully, but these errors were encountered: