oxidecomputer / oxidecomputer/quartz
DIMM temperature flicker on Cosmo
Nobody has claimed this yet.
- Dominant language
- VHDL
- Stars
- 22
- Forks
- 2
- Avg merge
- 9h 38m
- Merged PRs (30d)
- 1
Description
@labbott and I noticed some weirdness in DIMM temperature readings:
https://github.com/user-attachments/assets/7240e7bf-d765-4181-9fb9-dd757ce60d05
This corresponds to intermittent TemperatureReadTimeout logs in the cosmo-spd ringbuf, which means that bus0/1_rx_byte_count didn't hit 2 bytes within 8 ms of polling (source)
The behavior is weirdly bistable: we'll have solid readings from all sensors for a while, then they'll flicker wildly for a time, then go back to being stable.
It's unclear if this is a Hubris or FPGA issue, but I'm slightly more suspicious of the FPGA.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with cosmo-spd/src/main.rs at the TemperatureReadTimeout handling and the bus0/1_rx_byte_count polling described in the issue. Investigate whether the intermittent timeouts originate in Hubris or the FPGA; done means identifying the cause and restoring stable DIMM temperature readings without the flicker.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- embedded-iot
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 30/100