Date: Wed, 21 Jan 2009 14:08:37 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org Cc: Andre Albsmeier <Andre.Albsmeier@siemens.com> Subject: Re: How to "detach" a foreign driver from a device so my driver can attach? Message-ID: <200901211408.37883.jhb@freebsd.org> In-Reply-To: <20081223173322.GA4123@curry.mchp.siemens.de> References: <20081216230430.GA24352@curry.mchp.siemens.de> <20081223173322.GA4123@curry.mchp.siemens.de>
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On Tuesday 23 December 2008 12:33:22 pm Andre Albsmeier wrote:
> On Wed, 17-Dec-2008 at 00:04:30 +0100, Andre Albsmeier wrote:
> > Hello all,
> >
> > I am writing a driver which attaches to the Host-PCI bridge. When
> > compiled into the kernel or loaded by the loader everything works
> > and the driver gets attached. This is due to the fact that I return
> > BUS_PROBE_SPECIFIC in my probe routine which gains over the -10000
> > returned by pci_hostb_probe() in i386/pci/pci_bus.c.
> >
> > However, when I want to load my driver via kldload this fails since
> > the hostb device has already been attached during kernel load (when
> > my driver was not present):
> >
> > hostb0@pci0:0:0: class=0x060000 card=0x11d510cf chip=0x35808086
rev=0x02 hdr=0x00
> >
> > What can I do to make my driver load via kldload?
> > Is there a way to detach the hostb0 from the Host-PCI bridge?
>
> Found the answer myself but will post it here in case anyone
> got a similar problem one day: I added the device detach method
> for the hostb driver to sys/i386/pci/pci_bus.c:
>
> --- sys/i386/pci/pci_bus.c.ORI 2007-08-17 08:12:33.000000000 +0200
> +++ sys/i386/pci/pci_bus.c 2008-12-23 13:34:35.000000000 +0100
> @@ -619,10 +619,13 @@
> return 0;
> }
>
> +static int pci_hostb_detach(device_t dev) { return 0; }
> +
> static device_method_t pci_hostb_methods[] = {
> /* Device interface */
> DEVMETHOD(device_probe, pci_hostb_probe),
> DEVMETHOD(device_attach, pci_hostb_attach),
> + DEVMETHOD(device_detach, pci_hostb_detach),
> DEVMETHOD(device_shutdown, bus_generic_shutdown),
> DEVMETHOD(device_suspend, bus_generic_suspend),
> DEVMETHOD(device_resume, bus_generic_resume),
>
> Now, when kldload'ing my driver, it can walk through all devices
> and detach hostb using device_detach().
In the case of hostb, this is wrong however. You want to attach as a child of
hostb as other devices (e.g. agp(4)) need to attach to host-pci bridges as
well.
--
John Baldwin
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