[sane-devel] SaneTwain and HP2200C
Wed, 14 Aug 2002 17:04:53 +0200
On Wed, Aug 14, 2002 at 10:29:39AM +0100, Martyn Ranyard wrote:
> b. (Good(tm) option) add to the network (and backend) protocol so that
> when the backend is waiting for something, it can be pinged (in the IP
> sense), to check it hasn't hanged.
There is a timeout of 3600 second on the server side so I guess the
shorter timeout comes from the client.
There was some disccussion about this topic some time ago, here is the
corresponding TODO list entry:
- saned times out after 60 minutes. Check if the watchdog timer is
really necessary (e.g. to avoid blocking scanners by one user).
Maybe add a command line option to saned to set the timeout.
Otherwise turn on TCP keep alive (where available) and (maybe) check
the connection from server side.
I don't know too much about TCP programming and noone else has yet
> This probably involves lots of work,
> but would mean that the front ends could give a better clue as to what is
> happening - and maybe a status message could be passed (In this case "Lamp
> warming up") so that the user knows that the program hasn't locked
> up. Because this would change the protocol, sanetwain would have to be
> updated, and the network timeout would not be a problem (send ping packet,
> recieve pong packet).
Better status messages are planned for SANE 2. Such changes can't be
done without a new standard.