The quirk's 8KB transfer clamp exposed raw character-device I/O to
the oversized-mapping stall fixed earlier, and its single tracker
turned a stranded request into a complete I/O stall. Without it an
S3X controller runs 128 trackers at its MDTS-derived transfer size
with no retries, failures, or timeouts, at about seven times the
serialized throughput.
Approved by: ngie (co-mentor)