-d handles only one connection, and then exits. Maybe PDF studio needs to
connect twice. If this is your case, you simply cannot use -d/-s. -s is
just the same but redirects output to syslog.
The next release will change this behavior to something similar to what -d
generally mean in other
AFAIK, no. Loglevel is only define using -s or -d. Both enable debug mode
which exits after first connection. The next sane release will change -d
behavior, and "quit after first connection" will only be enabled if
explicitly set (-o|--once).
You could temporarily build from unstable source
root@raspberrypi:~:x86$ saned -d256
[saned] main: starting debug mode (level 256)
[saned] read_config: searching for config file
[saned] read_config: done reading config
[saned] saned (AF-indep+IPv6) from sane-backends 1.0.24 starting up
[saned] do_bindings: trying to get port for service
