Hiten Pandya wrote:
> On Mon, Mar 11, 2002 at 11:55:34AM -0800, Terry Lambert wrote:
> > This means that it's trying to register a driver with a
> > subsystem that has not yet been initialized.  You probably
> > need to split it off, and initialize it seperately ysing a
> > SYSINIT in the SI_SUB_DRIVERS, SI_ORDER_ANY.  If you have
> > trouble doing this, let me know, and I can take a look at
> > it for you (it's going to be a bit of a pain if it's allowed
> > to be loaded later; if so, the easiest thing to do is to
> > simply load it later, e.g. in /etc/rc.local).
> >
> Hmm.  AFAIK, All I did was to add the PERFMON driver to the kernel
> configuration file, and when I compiled and installed the kernel, and
> booted ofcourse, it came up with the error.


The perfmon_init() in /sys/i386/i386/perfmon.c makes a call to
make_dev().  With devfs, you can't call this until the device
subsystem has been initialized.

The perfmon_init() is called from /sys/i386/i386/machdep.c in
cpu_startup(), which is called as a result of:

        SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL)

which happens before SI_SUB_DRIVERS.

So to fix it, you would split the perfmon_init into a
perfmon_init() and a perfmon_init_dev().  The perfmon_init_dev()
code (in perfmon.c) would look like:

        static void perfmon_init_dev __P((void *));
        SYSINIT(cpu, SI_SUB_DRIVERS, SI_ORDER_ANY, perfmon_init_dev, NULL)

        /* ARGSUSED */
        static void
                void *dummy;
                 make_dev(&perfmon_cdevsw, 32, UID_ROOT, GID_KMEM,
                          0640, "perfmon");

The SI_ORDER_ANY makes it the lowest priority to happen at
SI_SUB_DRIVERS, which guaranteees that it's called *after*,
which avoids the problem.

In other words, it's a pretty rivial hack.

If someone wants to commit the code, the code I've listed
above is pretty much exactly what you'd need.

-- Terry

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