On Tue, 30 May 2000, you wrote:
> There is my iopener led driver that might be a good stard. I'm
> writing some articles about this now, but have been so swamped that
> I'm not sure when I'll get them done :-(. You can download the led
> driver from:
> http://people.freebsd.org/~imp/led.tar.gz
> Please let me know if you have problems with this, or comments on
> this.
This was the example I was looking for. I compiled it as a module
with a few changes to
led_identify (driver_t *driver, device_t parent)
{
devclass_t dc;
device_t child;
dc = devclass_find("led");
if (devclass_get_device(dc, 0) == NULL) {
child = BUS_ADD_CHILD(parent, 0, "led", -1);
device_set_desc(child, "MrLED");
bus_set_resource(child, SYS_RES_IOPORT, 0, LED_IOADDR, 1);
}
print_devclass_list();
}
For driver hacking in 4.0 I have options DDB and BUS_DEBUG in the
kernel I use. I strongly recommend any follow up documentation to
encourage the use of both of those. The ability to use all of those
print_XXX()'s in subr_bus.c was very illuminating to *this* novice 4.0
hacker.
I kldloaded / kldunloaded this several times and then went and studied
the message log. I am reasonably confident that things are behaving.
At least there is no overt evidence of leaks or panics.
My aberrant code was very close to this. I had determined I needed a
msm_identify() and within it I was calling BUS_ADD_CHILD. At 1st with
no conditional and then I had a problem with arguments.
BUS_ADD_CHILD(parent, ISA_ORDER_SPECULATIVE, "msm", 0) definitely gave
me grief.
Also I had DEVMETHOD(device_detach, bus_generic_detach) in my
msm_methods. I added an msm_detach instead, that is currently stubbed
out to only the return 0 statement. Making only those changes allows
me to now kldload & unload my driver with results equivalent to
the LED driver. Thank you...Sluething out the right example
always makes life so easy.
Conceptually I'm not sure I clearly understand what gets left behind
in the kernel after a kldunload, but I'll ponder on that and in the
mean time continue to whup the driver into shape.
1 3 0 1 3
13013
BOB
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