24 lines
1.8 KiB
Markdown
24 lines
1.8 KiB
Markdown
# Open questions
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The genuinely open, thinking-worthy problems — nothing here is resolved. Analyses and settled facts live in the device docs; each entry points at the doc that holds its detail. Read `state.md` first for placement context.
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## 1. Can ConnectX-5 MCIA reach the BCM? (decide on arrival)
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The decisive unknown for product diagnostics coverage ([nics/connectx-5/](nics/connectx-5/README.md)):
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- Does firmware MCIA accept **arbitrary I2C device addresses**? The register format allows it (8-bit field, per-access status — verified in `mlx5_ifc.h`); firmware acceptance is the unknown.
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- Does the BCM bridge **tolerate an offset write before its SMI read phase**? MCIA has no raw-read encoding, so this module-side property is the whole question — and it is testable on the X520 before the card arrives.
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- If no to either: product diagnostics via the Marvell/Aquantia modules only.
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## 2. ECD run disturbance
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The BCM ECD run blips the link (PMA 1.1 latch-low catches a drop even with the break-link bit clear). Until the disturbance is characterized, length measurement is a between-runs operation, not a during-run one ([modules/fs/](modules/fs/README.md)).
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## 3. Pre-FEC correlation run
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The register question is answered (post-FEC vs corrected-by-iteration histogram located); the graded-noise correlation run that verifies the expected ordering has not happened. Design and instrument: [modules/fibergaga/](modules/fibergaga/README.md).
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## 4. Wiitek VCT — pursue or leave dead?
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No confirmed-safe path exists (every candidate lands in the µC danger window). The open decision is whether the capability is worth the NDA route or a sacrificial unit — the product doesn't need it for length ([modules/wiitek/](modules/wiitek/README.md), [modules/README.md](modules/README.md)).
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