Re: [hpoj-devel] ptal-mlcd and hotplug scripts

[Allen B. <ba...@lo...>]

"PASCHAL,DAVID (HP-Roseville,ex1)" wrote:
> 
> Hi, Allen.
> 
> Allen Barnett wrote:
> > Would it be possible for ptal-printd to
> > receive notification from ptal-mlcd that ptal-mlcd is shutting itself
> > down?
> That's a bit of a problem.  From what I've heard, systems running LPRng hang
> unless ptal-printd is running at startup.

I "fixed" this problem by commenting the 'checkpc' command out of the
lpd init script. There's definitely a race condition between the
execution of the runlevel init scripts and the startup of the kernel USB
hub daemon and the subsequent execution of hotplug scripts; the kernel
printer module may not even be loaded when the lpr init script executes.

>  One solution may be to:
> - run ptal-printd from an init script (before LPRng is initialized),
> - load ptal-mlcd from a hotplug script (if not from an init script), and
> - use a descriptive PTAL device name like mlc:usb:hpojg85 instead of the
> uncreative mlc:usb:X that I typically use that corresponds to the
> /dev/usb/lpX in use.

OK. I didn't realize that 'X' was arbitrary.

So, starting and stopping ptal-printd should probably be the
responsibility of the printing system, not the hotplugging system. Can
one ptal-printd process tolerate the stopping and restarting of
ptal-mlcd?

OTOH, how about adding the ability of ptal-mlcd to execute a script when
it starts and stops? It  could start and stop ptal-printd and enable and
disable print queues and so on. 

Thanks,
Allen