Re: [PATCH] Make discovery mode of bluetooth CUPS backend work with CUPS 1.4.0

[Marcel Holtmann <marcel@holtmann.org>]

Hi Till,

> The new CUPS 1.4.x does device discovery only for a given time frame
> requested by the client (printer setup tool, "lpinfo" command). CUPS's
> default for CUPS-1.3.x-ish requests without timeout specification
> seems to be 10 seconds. CUPS starts all backends at once in the
> beginning (in parallel) and kills every backend which remains running
> at the end of the timeout. It accepts output from the backends
> whenever it occurs not only when the backend finishes, so a backend
> can search for printers infinitely long if it outputs every found
> device immediately. Then all printers found during CUPS' timeout are
> taken into account.
> 
> The bluetooth backend of 4.48 asks the Bluetooth daemon for printers
> and collects results for 10 seconds and after that it outputs
> them. This takes a total of 10.5 sec and so CUPS kills the backend
> right before it answers (at least with the 10-second default timeout),
> resulting in Bluetooth printers never being discovered by CUPS.
> 
> This change fixes it by making each new printer added to the list
> being output immediately. Note that the list structure cannot be
> removed from cups/main.c as otherwise we would get duplicate
> listings. Also important is the addition of unbuffered output on
> stdout.
> ---
>   ChangeLog   |    2 +
>   cups/main.c |   63 
> +++++++++++++++++++++++-----------------------------------
>   2 files changed, 27 insertions(+), 38 deletions(-)

I can't use git am to apply this patch. Someone has to fix this for me.

Regards

Marcel