maybe_recover_transfer_error previously handled only the first-tier
codes (UsbTransaction, Resource, Stall, BabbleDetected, DataBuffer,
Trb, SplitTransaction) and silently returned Ok(false) for every
other completion code via a catch-all arm.
Cross-referenced Linux 7.1 drivers/usb/host/xhci-ring.c
handle_tx_event() (line 2608+) and handle_transferless_tx_event()
(line 2561+) to add explicit recovery for the remaining ~29 codes:
- Stopped/StoppedLengthInvalid/StoppedShortPacket: restart endpoint
+ retry (up to MAX_SOFT_RETRY), then hard-reset
- InvalidStreamType/InvalidStreamId: soft reset + retry, then
hard-reset
- IncompatibleDevice: disable slot (device must re-enumerate)
- MissedService/NoPingResponse: log informational, surface to caller
- ContextState/Parameter: hard-reset to resync driver/xHC state
- Bandwidth/BandwidthOverrun/SecondaryBandwidth: log, no transfer
recovery (config must change)
- IsochBuffer: hard-reset endpoint
- MaxExitLatencyTooLarge: log, surface
- EventLost/Undefined: hard-reset (event ring may be corrupted)
- SlotNotEnabled/EndpointNotEnabled/NoSlotsAvailable: log driver
state mismatch
- CommandRingStopped/CommandAborted: log xHC state confusion
- Reserved/vendor: default arm logs explicitly
Added completion_code_to_errno() mapping transfer completion codes
to POSIX errnos matching Linux 7.1 semantics:
Stall -> EPIPE
BabbleDetected -> EOVERFLOW
UsbTransaction/SplitTransaction/IncompatibleDevice -> EPROTO
Trb -> EILSEQ
DataBuffer -> ENOSR
SlotNotEnabled/EndpointNotEnabled/NoSlotsAvailable -> ENODEV
default -> EIO
Rewrote handle_transfer_event_trb() to use the new errno mapping
instead of always returning EIO.
Added 14 unit tests covering all errno mappings and transfer
event handling paths. Full suite (41 tests) passes.
Red Bear OS
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