There was a complicated scheme to increase the time between keepalives
from 3 minutes up to as much as 24 hours in an attempt to reduce
network traffic from idle X terminals. X terminals receiving X
traffic, or receiving user input would use the 3 minute value; X
terminals without any network traffic would use a longer value.
However, this was actually broken -- any activity in the X server,
either client requests or user input, would end up resetting the
keepalive timeout, so a user mashing on the keyboard would never
discover that the XDMCP master had disappeared and have the session
terminated, which was precisely the design goal of the XDMCP keepalive
mechanism.
Instead of attempting to fix this, accept the cost of a pair of XDMCP
packets once every three minutes and just perform keepalives
regularly.
This will also make reworking the block and wakeup handler APIs to
eliminate select masks easier.
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
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