[cups.development] [RFE] STR #3992: Side-channel command for DISCARD_OUTPUT

[Tim Waugh]

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[STR New]

When cancelling a job, the backend continues to send data that was queued
before the job had been cancelled.  It can be useful to tell the backend
to discard data buffered up to send to the device, in preparation for
sending a short reset sequence, in some cases saving paper and ink.

This seems to be different to SOFT_RESET, which appears to be a command
for the backend to perform a reset for that type of connection (e.g. USB),
rather than for this model of device.

This DISCARD_OUTPUT side-channel command could be implemented in
runloop.c, and drivers could make use of it when cancelling jobs.

Link: http://www.cups.org/str.php?L3992
Version:  -feature