Re: [HPLIP-Devel] Bug: hplip >=1.6.12 breaks support for the sane network daemon

[Johannes M. <js...@su...>]

Hello David,

On Jul 24 19:24 Suffield, David wrote (shortened):
> This looks like a case where we don't necessarily follow
> the Sane specification. Since the old hpaio code ignored localOnly
> and seemed to work ok, I see no reason for not changing it back.

Yesterday I did a very quick search what other backends in the SANE
software do and it seems they usually ignore localOnly too.

For your information I attached the gzipped output of
  for f in sane-backends-1.0.18/backend/*.c
  do echo $f
     grep local_only $f
     echo
  done

It seems the net backend ist the only one which implements
a test for local_only: "if (local_only)".

Because of this I got the assumtion that perhaps local_only
is only useful for the net backend to avoid that SANE devices
with "net" are reported duplicated to the frontend.

SANE devices with "net" can be also locally connected scanners
(e.g. via USB) because saned and net can both run on "localhost"
like on my workstation:
-------------------------------------------------------------------
# scanimage -L
device `hpaio:/usb/HP_LaserJet_1220?serial=00XXXXXXXXXX'
 is a Hewlett-Packard HP_LaserJet_1220 all-in-one
device `hpaio:/net/Officejet_7200_series?ip=10.10.100.100'
 is a Hewlett-Packard Officejet_7200_series all-in-one
device `plustek:libusb:001:006'
 is a Canon N1240U/LiDE30 USB flatbed scanner
device `net:localhost:hpaio:/usb/HP_LaserJet_1220?serial=00XXXXXXXXXX'
 is a Hewlett-Packard HP_LaserJet_1220 all-in-one
device `net:localhost:plustek:libusb:001:006'
 is a Canon N1240U/LiDE30 USB flatbed scanner
-------------------------------------------------------------------
There is no good reason why there shouldn't be also a SANE device
`net:localhost:hpaio:/net/Officejet_7200_series?ip=10.10.100.100'
when I explicitely run saned and net on my workstation.

Of course one could discuss why someone should run saned and net
on his workstation for his locally connected scanners.
Usually this is the easiest way to get user access in problematic
cases (because saned runs as root) like for parallel port scanners
or if someone might be fed-up with the udev/HAL/resmgr magic ;-)


Kind Regards
Johannes Meixner
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