Date: Fri, 30 Oct 1998 09:44:35 +0000 (GMT) From: Doug Rabson <dfr@nlsystems.com> To: Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp> Cc: John Hay <jhay@mikom.csir.co.za>, FreeBSD-hackers <hackers@FreeBSD.ORG> Subject: Re: kld screensavers Message-ID: <Pine.BSF.4.01.9810300936140.366-100000@herring.nlsystems.com> In-Reply-To: <199810291457.XAA12116@zodiac.mech.utsunomiya-u.ac.jp>
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On Thu, 29 Oct 1998, Kazutaka YOKOTA wrote:
>
> >It looks about right and SI_SUB_PSEUDO is sufficiently late that it
> >shouldn't disturb anything. Any time after SI_SUB_CONFIGURE should work I
> >think.
> >
> >It would be nice if the add_scrn_saver/remove_scrn_saver goop was factored
> >into a generic module event handler which can be used by all screen
> >savers. Have a look at the CDEV_MODULE #define in sys/conf.h for a
> >possible way of doing this.
> >
> >If the generic module handler chains onto an optional user-supplied
> >handler, then extra initialisation (allocating message in this case) can
> >be done by each saver without repeating the registration code.
>
> You mean something like this?
>
> 1. Define generic_screen_saver_module_handler() in syscons.c or somewhere.
> 2. Each screen saver module define its own event handler. It will call
> the generic handler first and then do its own extra house keeping.
Thats more or less what I was suggesting. Simple screen savers wouldn't
even need an event handler. Maybe something like:
struct saver_module_data {
modeventhand_t chainevh;
void* chainarg;
void (*saver)(int);
};
#defined SAVER_MODULE(name, fn, evh, arg) \
static struct saver_module_data name##_saver_mod = { \
evh, arg, fn \
}; \
\
static moduledata_t name##_mod = { \
#name, \
saver_module_handler, \
&name##_saver_mod \
}; \
DECLARE_MODULE(name, name##_mod, SI_SUB_PSEUDO, SI_ORDER_MIDDLE)
static int
saver_module_handler(module_t mod, modeventtype_t type, void *arg)
{
struct saver_module_data *data = arg;
switch (type) {
case MOD_LOAD:
return add_scrn_saver(data->saver);
case MOD_UNLOAD:
return remove_scrn_saver(data->saver);
default:
printf("star_saver module unknown event: 0x%x\n", type);
}
if (data->chainevh)
return data->chainevh(mod, what, data->chainarg);
else
return 0;
}
--
Doug Rabson Mail: dfr@nlsystems.com
Nonlinear Systems Ltd. Phone: +44 181 951 1891
Fax: +44 181 381 1039
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