linuxboot / linuxboot/heads

PCIe bifurcation doesn't work

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#351 4 comments 0 reactions 0 assignees View on GitHub

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Description

If a PCIe slot is using bifurcation to implement a dual x8 ports as an example on a x16 port, the attached PCIe device is not recognized. That is an issue on most OCP nodes which are intensively using PCIe bifurcation. A workaround is to directly plugged the PCI card into the master slot.

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the failure with a PCIe x16 slot bifurcated into dual x8 ports, comparing it with the direct master-slot workaround. Trace PCIe device enumeration in the firmware and document a reproducible configuration and test showing that both attached devices are recognized.

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Assessment

Domain
embedded-iot
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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