Interfacing (DSI, CSI, I2C, etc.) • Re: Pi5 MIPI CRC Check

ECC is handled by hardware. CRC is ignored. (We don't discard packets with bad CRC, because by the time CRC arrives, they may already have been partially written to memory or sent to the ISP. )

It should be possible to detect and report CRC errors, but currently the driver does not.

IRQ flags:
- The INACTIVE (bit 24) and UNMATCHED (bit 23) flags mean more or less the same thing: A packet was received with (VC,DT) that didn't match any active output channels. It could possibly be due to a header error (since ECC is not foolproof).
- The LENGTH_LIMIT (bit 22) flag means that an image or metadata was larger than the buffer size, and was trimmed. Conceivably, that could also be caused by a missing FE.
- The lower nybbles represent frame start and frame end events on each of the VCs. It looks like you are using VC 0 and VC 1.
The error flags don't cause an interrupt by themselves; they get reported along with the next FS/FE interrupt. These all come from the CSIDMA block, after CRC has already been stripped.

What bit rate does the sensor use? What is printed by CFE's sensor_link_rate() function?

Statistics: Posted by njh — Fri Jul 18, 2025 9:48 am

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