SpiDevice cancel safety: always set CS pin to high on drop #3844
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If a transfer is dropped, the CS will stay in a low state, which seems to be unsafe.
Dirbaio
reviewed
Feb 4, 2025
| @@ -97,11 +102,10 @@ where | |||
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| // On failure, it's important to still flush and deassert CS. | |||
| let flush_res = bus.flush().await; | |||
| let cs_res = self.cs.set_high(); | |||
| drop(cs_drop); | |||
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this will silently swallow the error.
I'd suggest doing cs_drop.defuse() and then do set_high as before so the error can be handled.
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Changed as you advised. Could you please take a look again?
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Currently, if a transfer is dropped, the CS will stay in a low state, which seems to be undesired. This uses
OnDropto guarantee that CS will be high regardless what happens.Note that it is currently still unsafe, at least for STM32, to drop an on-going SPI transfer. More investigation on this is TBD. Some suggestions on this would be nice, e.g., whether it's desired to implement cancel safety for SPI transfers.