They don't have BUSY de-asserted by the time they ACK (and thus cause
an interrupt). The workaround is to try seeing if the BUSY will be
de-asserted soon, and if not, to use an incremental backoff and
semi-polled mode instead of the fixed timeout with 1/2 s we've been
using previously (that caused the printer to run really slooow).
Printers that have been working previously should not be affected by
this.
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