[PATCH] ppbus/ppc locking

[Bruce M. Simpson]

John Baldwin wrote:
> ...
> Hmm you don't see /dev/lpt0 and /dev/lpt0.ctl via ls(1)?  The attach routine 
> creates the devices via make_dev() right after the "interrupt-driven port" 
> message.
>
>   

I see /dev/lpt0.ctl, but not /dev/lpt0.

data points:
* The printer is a shonky old GCC Elite 600.
* The BIOS is configured to expose LPT0 at "the usual ISA I/O address" 
w/interrupt mode 0x378 irq 7.
* There are no error messages from lpt0 in dmesg, it does say lpt0: 
[MPSAFE].
* I load lpt.ko from loader.conf on boot.
* If I try to kldunload lpt, it panics in destroy_devl() called from 
lpt_detach().
* I get the same results if the printer attached via lpt is switched on 
or off on boot.

cups will just complain the printer isn't connected, as /dev/lpt0 
doesn't exist.

If I boot with bootverbose enabled, I see nothing which indicates that 
the make_dev() call has failed.