dev/pci/vga_pci.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
/*
 * Simple driver for PCI VGA display devices.  Drivers such as agp(4) and
 * drm(4) should attach as children of this device.
 *
 * XXX: The vgapci name is a hack until we somehow merge the isa vga driver
 * in or rename it.
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

#if defined(__amd64__) || defined(__i386__)
#include <vm/vm.h>
#include <vm/pmap.h>
#endif

#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>

#include <compat/x86bios/x86bios.h> /* To re-POST the card. */

struct vga_resource {
	struct resource	*vr_res;
	int	vr_refs;
};

struct vga_pci_softc {
	device_t	vga_msi_child;	/* Child driver using MSI. */
	struct vga_resource vga_bars[PCIR_MAX_BAR_0 + 1];
	struct vga_resource vga_bios;
};

SYSCTL_DECL(_hw_pci);

static struct vga_resource *lookup_res(struct vga_pci_softc *sc, int rid);
static struct resource *vga_pci_alloc_resource(device_t dev, device_t child,
    int type, int *rid, rman_res_t start, rman_res_t end, rman_res_t count,
    u_int flags);
static int	vga_pci_release_resource(device_t dev, device_t child,
    struct resource *r);

int vga_pci_default_unit = -1;
SYSCTL_INT(_hw_pci, OID_AUTO, default_vgapci_unit, CTLFLAG_RDTUN,
    &vga_pci_default_unit, -1, "Default VGA-compatible display");

int
vga_pci_is_boot_display(device_t dev)
{
	int unit;
	device_t pcib;
	uint16_t config;

	/* Check that the given device is a video card */
	if ((pci_get_class(dev) != PCIC_DISPLAY &&
	    (pci_get_class(dev) != PCIC_OLD ||
	     pci_get_subclass(dev) != PCIS_OLD_VGA)))
		return (0);

	unit = device_get_unit(dev);

	if (vga_pci_default_unit >= 0) {
		/*
		 * The boot display device was determined by a previous
		 * call to this function, or the user forced it using
		 * the hw.pci.default_vgapci_unit tunable.
		 */
		return (vga_pci_default_unit == unit);
	}

	/*
	 * The primary video card used as a boot display must have the
	 * "I/O" and "Memory Address Space Decoding" bits set in its
	 * Command register.
	 *
	 * Furthermore, if the card is attached to a bridge, instead of
	 * the root PCI bus, the bridge must have the "VGA Enable" bit
	 * set in its Control register.
	 */

	pcib = device_get_parent(device_get_parent(dev));
	if (device_get_devclass(device_get_parent(pcib)) ==
	    devclass_find("pci")) {
		/*
		 * The parent bridge is a PCI-to-PCI bridge: check the
		 * value of the "VGA Enable" bit.
		 */
		config = pci_read_config(pcib, PCIR_BRIDGECTL_1, 2);
		if ((config & PCIB_BCR_VGA_ENABLE) == 0)
			return (0);
	}

	config = pci_read_config(dev, PCIR_COMMAND, 2);
	if ((config & (PCIM_CMD_PORTEN | PCIM_CMD_MEMEN)) == 0)
		return (0);

	/*
	 * Disable interrupts until a chipset driver is loaded for
	 * this PCI device. Else unhandled display adapter interrupts
	 * might freeze the CPU.
	 */
	pci_write_config(dev, PCIR_COMMAND, config | PCIM_CMD_INTxDIS, 2);

	/* This video card is the boot display: record its unit number. */
	vga_pci_default_unit = unit;
	device_set_flags(dev, 1);

	return (1);
}

static void
vga_pci_reset(device_t dev)
{
	int ps;
	/*
	 * FLR is unsupported on GPUs so attempt a power-management reset by cycling
	 * the device in/out of D3 state.
	 * PCI spec says we can only go into D3 state from D0 state.
	 * Transition from D[12] into D0 before going to D3 state.
	 */
	ps = pci_get_powerstate(dev);
	if (ps != PCI_POWERSTATE_D0 && ps != PCI_POWERSTATE_D3)
		pci_set_powerstate(dev, PCI_POWERSTATE_D0);
	if (pci_get_powerstate(dev) != PCI_POWERSTATE_D3)
		pci_set_powerstate(dev, PCI_POWERSTATE_D3);
	pci_set_powerstate(dev, ps);
}

void *
vga_pci_map_bios(device_t dev, size_t *size)
{
	struct vga_resource *vr;
	struct resource *res;
	device_t pcib;
	uint32_t rom_addr;
	uint16_t config;
	volatile unsigned char *bios;
	int i, rid, found;

#if defined(__amd64__) || defined(__i386__)
	if (vga_pci_is_boot_display(dev)) {
		/*
		 * On x86, the System BIOS copy the default display
		 * device's Video BIOS at a fixed location in system
		 * memory (0xC0000, 128 kBytes long) at boot time.
		 *
		 * We use this copy for the default boot device, because
		 * the original ROM may not be valid after boot.
		 */

		*size = VGA_PCI_BIOS_SHADOW_SIZE;
		return (pmap_mapbios(VGA_PCI_BIOS_SHADOW_ADDR, *size));
	}
#endif

	pcib = device_get_parent(device_get_parent(dev));
	if (device_get_devclass(device_get_parent(pcib)) ==
	    devclass_find("pci")) {
		/*
		 * The parent bridge is a PCI-to-PCI bridge: check the
		 * value of the "VGA Enable" bit.
		 */
		config = pci_read_config(pcib, PCIR_BRIDGECTL_1, 2);
		if ((config & PCIB_BCR_VGA_ENABLE) == 0) {
			config |= PCIB_BCR_VGA_ENABLE;
			pci_write_config(pcib, PCIR_BRIDGECTL_1, config, 2);
		}
	}

	switch(pci_read_config(dev, PCIR_HDRTYPE, 1)) {
	case PCIM_HDRTYPE_BRIDGE:
		rid = PCIR_BIOS_1;
		break;
	case PCIM_HDRTYPE_CARDBUS:
		rid = 0;
		break;
	default:
		rid = PCIR_BIOS;
		break;
	}
	if (rid == 0)
		return (NULL);
	res = vga_pci_alloc_resource(dev, NULL, SYS_RES_MEMORY, &rid, 0,
	    ~0, 1, RF_ACTIVE);

	if (res == NULL) {
		device_printf(dev, "vga_pci_alloc_resource failed\n");
		return (NULL);
	}
	bios = rman_get_virtual(res);
	*size = rman_get_size(res);
	for (found = i = 0; i < hz; i++) {
		found = (bios[0] == 0x55 && bios[1] == 0xaa);
		if (found)
			break;
		pause("vgabios", 1);
	}
	if (found)
		return (__DEVOLATILE(void *, bios));
	if (bootverbose)
		device_printf(dev, "initial ROM mapping failed -- resetting\n");

	/*
	 * Enable ROM decode
	 */
	vga_pci_reset(dev);
	rom_addr = pci_read_config(dev, rid, 4);
	rom_addr &= 0x7ff;
	rom_addr |= rman_get_start(res) | 0x1;
	pci_write_config(dev, rid, rom_addr, 4);
	vr = lookup_res(device_get_softc(dev), rid);
	vga_pci_release_resource(dev, NULL, vr->vr_res);

	/*
	 * re-allocate
	 */
	res = vga_pci_alloc_resource(dev, NULL, SYS_RES_MEMORY, &rid, 0,
	    ~0, 1, RF_ACTIVE);
	if (res == NULL) {
		device_printf(dev, "vga_pci_alloc_resource failed\n");
		return (NULL);
	}
	bios = rman_get_virtual(res);
	*size = rman_get_size(res);
	for (found = i = 0; i < 3*hz; i++) {
		found = (bios[0] == 0x55 && bios[1] == 0xaa);
		if (found)
			break;
		pause("vgabios", 1);
	}
	if (found)
		return (__DEVOLATILE(void *, bios));
	device_printf(dev, "ROM mapping failed\n");
	vr = lookup_res(device_get_softc(dev), rid);
	vga_pci_release_resource(dev, NULL, vr->vr_res);
	return (NULL);
}

void
vga_pci_unmap_bios(device_t dev, void *bios)
{
	struct vga_resource *vr;
	int rid;

	if (bios == NULL) {
		return;
	}

#if defined(__amd64__) || defined(__i386__)
	if (vga_pci_is_boot_display(dev)) {
		/* We mapped the BIOS shadow copy located at 0xC0000. */
		pmap_unmapdev(bios, VGA_PCI_BIOS_SHADOW_SIZE);

		return;
	}
#endif
	switch(pci_read_config(dev, PCIR_HDRTYPE, 1)) {
	case PCIM_HDRTYPE_BRIDGE:
		rid = PCIR_BIOS_1;
		break;
	case PCIM_HDRTYPE_CARDBUS:
		rid = 0;
		break;
	default:
		rid = PCIR_BIOS;
		break;
	}
	if (rid == 0)
		return;
	/*
	 * Look up the PCIR_BIOS resource in our softc.  It should match
	 * the address we returned previously.
	 */
	vr = lookup_res(device_get_softc(dev), rid);
	KASSERT(vr->vr_res != NULL, ("vga_pci_unmap_bios: bios not mapped"));
	KASSERT(rman_get_virtual(vr->vr_res) == bios,
	    ("vga_pci_unmap_bios: mismatch"));
	vga_pci_release_resource(dev, NULL, vr->vr_res);
}

int
vga_pci_repost(device_t dev)
{
#if defined(__amd64__) || defined(__i386__)
	x86regs_t regs;

	if (!vga_pci_is_boot_display(dev))
		return (EINVAL);

	if (x86bios_get_orm(VGA_PCI_BIOS_SHADOW_ADDR) == NULL)
		return (ENOTSUP);

	x86bios_init_regs(&regs);

	regs.R_AH = pci_get_bus(dev);
	regs.R_AL = (pci_get_slot(dev) << 3) | (pci_get_function(dev) & 0x07);
	regs.R_DL = 0x80;

	device_printf(dev, "REPOSTing\n");
	x86bios_call(&regs, X86BIOS_PHYSTOSEG(VGA_PCI_BIOS_SHADOW_ADDR + 3),
	    X86BIOS_PHYSTOOFF(VGA_PCI_BIOS_SHADOW_ADDR + 3));

	x86bios_get_intr(0x10);

	return (0);
#else
	return (ENOTSUP);
#endif
}

static int
vga_pci_probe(device_t dev)
{

	switch (pci_get_class(dev)) {
	case PCIC_DISPLAY:
		break;
	case PCIC_OLD:
		if (pci_get_subclass(dev) != PCIS_OLD_VGA)
			return (ENXIO);
		break;
	default:
		return (ENXIO);
	}

	/* Probe default display. */
	vga_pci_is_boot_display(dev);

	device_set_desc(dev, "VGA-compatible display");
	return (BUS_PROBE_GENERIC);
}

static int
vga_pci_attach(device_t dev)
{

	bus_generic_probe(dev);

	/* Always create a drmn child for now to make it easier on drm. */
	device_add_child(dev, "drmn", -1);
	bus_generic_attach(dev);

	if (vga_pci_is_boot_display(dev))
		device_printf(dev, "Boot video device\n");

	return (0);
}

static int
vga_pci_suspend(device_t dev)
{

	return (bus_generic_suspend(dev));
}

static int
vga_pci_detach(device_t dev)
{
	int error;

	error = bus_generic_detach(dev);
	if (error == 0)
		error = device_delete_children(dev);
	return (error);
}

static int
vga_pci_resume(device_t dev)
{

	return (bus_generic_resume(dev));
}

/* Bus interface. */

static int
vga_pci_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{

	return (BUS_READ_IVAR(device_get_parent(dev), dev, which, result));
}

static int
vga_pci_write_ivar(device_t dev, device_t child, int which, uintptr_t value)
{

	return (EINVAL);
}

static int
vga_pci_setup_intr(device_t dev, device_t child, struct resource *irq,
    int flags, driver_filter_t *filter, driver_intr_t *intr, void *arg,
    void **cookiep)
{
	return (BUS_SETUP_INTR(device_get_parent(dev), dev, irq, flags,
	    filter, intr, arg, cookiep));
}

static int
vga_pci_teardown_intr(device_t dev, device_t child, struct resource *irq,
    void *cookie)
{
	return (BUS_TEARDOWN_INTR(device_get_parent(dev), dev, irq, cookie));
}

static struct vga_resource *
lookup_res(struct vga_pci_softc *sc, int rid)
{
	int bar;

	if (rid == PCIR_BIOS)
		return (&sc->vga_bios);
	bar = PCI_RID2BAR(rid);
	if (bar >= 0 && bar <= PCIR_MAX_BAR_0)
		return (&sc->vga_bars[bar]);
	return (NULL);
}

static struct resource *
vga_pci_alloc_resource(device_t dev, device_t child, int type, int *rid,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
	struct vga_resource *vr;

	switch (type) {
	case SYS_RES_MEMORY:
	case SYS_RES_IOPORT:
		/*
		 * For BARs, we cache the resource so that we only allocate it
		 * from the PCI bus once.
		 */
		vr = lookup_res(device_get_softc(dev), *rid);
		if (vr == NULL)
			return (NULL);
		if (vr->vr_res == NULL)
			vr->vr_res = bus_alloc_resource(dev, type, rid, start,
			    end, count, flags);
		if (vr->vr_res != NULL)
			vr->vr_refs++;
		return (vr->vr_res);
	}
	return (bus_alloc_resource(dev, type, rid, start, end, count, flags));
}

static int
vga_pci_release_resource(device_t dev, device_t child, struct resource *r)
{
	struct vga_resource *vr;
	int error;

	switch (rman_get_type(r)) {
	case SYS_RES_MEMORY:
	case SYS_RES_IOPORT:
		/*
		 * For BARs, we release the resource from the PCI bus
		 * when the last child reference goes away.
		 */
		vr = lookup_res(device_get_softc(dev), rman_get_rid(r));
		if (vr == NULL)
			return (EINVAL);
		if (vr->vr_res == NULL)
			return (EINVAL);
		KASSERT(vr->vr_res == r, ("vga_pci resource mismatch"));
		if (vr->vr_refs > 1) {
			vr->vr_refs--;
			return (0);
		}
		KASSERT(vr->vr_refs > 0,
		    ("vga_pci resource reference count underflow"));
		error = bus_release_resource(dev, r);
		if (error == 0) {
			vr->vr_res = NULL;
			vr->vr_refs = 0;
		}
		return (error);
	}

	return (bus_release_resource(dev, r));
}

/* PCI interface. */

static uint32_t
vga_pci_read_config(device_t dev, device_t child, int reg, int width)
{

	return (pci_read_config(dev, reg, width));
}

static void
vga_pci_write_config(device_t dev, device_t child, int reg,
    uint32_t val, int width)
{

	pci_write_config(dev, reg, val, width);
}

static int
vga_pci_enable_busmaster(device_t dev, device_t child)
{

	return (pci_enable_busmaster(dev));
}

static int
vga_pci_disable_busmaster(device_t dev, device_t child)
{

	return (pci_disable_busmaster(dev));
}

static int
vga_pci_enable_io(device_t dev, device_t child, int space)
{

	device_printf(dev, "child %s requested pci_enable_io\n",
	    device_get_nameunit(child));
	return (pci_enable_io(dev, space));
}

static int
vga_pci_disable_io(device_t dev, device_t child, int space)
{

	device_printf(dev, "child %s requested pci_disable_io\n",
	    device_get_nameunit(child));
	return (pci_disable_io(dev, space));
}

static int
vga_pci_get_vpd_ident(device_t dev, device_t child, const char **identptr)
{

	return (pci_get_vpd_ident(dev, identptr));
}

static int
vga_pci_get_vpd_readonly(device_t dev, device_t child, const char *kw,
    const char **vptr)
{

	return (pci_get_vpd_readonly(dev, kw, vptr));
}

static int
vga_pci_set_powerstate(device_t dev, device_t child, int state)
{

	device_printf(dev, "child %s requested pci_set_powerstate\n",
	    device_get_nameunit(child));
	return (pci_set_powerstate(dev, state));
}

static int
vga_pci_get_powerstate(device_t dev, device_t child)
{

	device_printf(dev, "child %s requested pci_get_powerstate\n",
	    device_get_nameunit(child));
	return (pci_get_powerstate(dev));
}

static int
vga_pci_assign_interrupt(device_t dev, device_t child)
{

	device_printf(dev, "child %s requested pci_assign_interrupt\n",
	    device_get_nameunit(child));
	return (PCI_ASSIGN_INTERRUPT(device_get_parent(dev), dev));
}

static int
vga_pci_find_cap(device_t dev, device_t child, int capability,
    int *capreg)
{

	return (pci_find_cap(dev, capability, capreg));
}

static int
vga_pci_find_next_cap(device_t dev, device_t child, int capability,
    int start, int *capreg)
{

	return (pci_find_next_cap(dev, capability, start, capreg));
}

static int
vga_pci_find_extcap(device_t dev, device_t child, int capability,
    int *capreg)
{

	return (pci_find_extcap(dev, capability, capreg));
}

static int
vga_pci_find_next_extcap(device_t dev, device_t child, int capability,
    int start, int *capreg)
{

	return (pci_find_next_extcap(dev, capability, start, capreg));
}

static int
vga_pci_find_htcap(device_t dev, device_t child, int capability,
    int *capreg)
{

	return (pci_find_htcap(dev, capability, capreg));
}

static int
vga_pci_find_next_htcap(device_t dev, device_t child, int capability,
    int start, int *capreg)
{

	return (pci_find_next_htcap(dev, capability, start, capreg));
}

static int
vga_pci_alloc_msi(device_t dev, device_t child, int *count)
{
	struct vga_pci_softc *sc;
	int error;

	sc = device_get_softc(dev);
	if (sc->vga_msi_child != NULL)
		return (EBUSY);
	error = pci_alloc_msi(dev, count);
	if (error == 0)
		sc->vga_msi_child = child;
	return (error);
}

static int
vga_pci_alloc_msix(device_t dev, device_t child, int *count)
{
	struct vga_pci_softc *sc;
	int error;

	sc = device_get_softc(dev);
	if (sc->vga_msi_child != NULL)
		return (EBUSY);
	error = pci_alloc_msix(dev, count);
	if (error == 0)
		sc->vga_msi_child = child;
	return (error);
}

static int
vga_pci_remap_msix(device_t dev, device_t child, int count,
    const u_int *vectors)
{
	struct vga_pci_softc *sc;

	sc = device_get_softc(dev);
	if (sc->vga_msi_child != child)
		return (ENXIO);
	return (pci_remap_msix(dev, count, vectors));
}

static int
vga_pci_release_msi(device_t dev, device_t child)
{
	struct vga_pci_softc *sc;
	int error;

	sc = device_get_softc(dev);
	if (sc->vga_msi_child != child)
		return (ENXIO);
	error = pci_release_msi(dev);
	if (error == 0)
		sc->vga_msi_child = NULL;
	return (error);
}

static int
vga_pci_msi_count(device_t dev, device_t child)
{

	return (pci_msi_count(dev));
}

static int
vga_pci_msix_count(device_t dev, device_t child)
{

	return (pci_msix_count(dev));
}

static bus_dma_tag_t
vga_pci_get_dma_tag(device_t bus, device_t child)
{

	return (bus_get_dma_tag(bus));
}

static device_method_t vga_pci_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		vga_pci_probe),
	DEVMETHOD(device_attach,	vga_pci_attach),
	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
	DEVMETHOD(device_suspend,	vga_pci_suspend),
	DEVMETHOD(device_detach,	vga_pci_detach),
	DEVMETHOD(device_resume,	vga_pci_resume),

	/* Bus interface */
	DEVMETHOD(bus_read_ivar,	vga_pci_read_ivar),
	DEVMETHOD(bus_write_ivar,	vga_pci_write_ivar),
	DEVMETHOD(bus_setup_intr,	vga_pci_setup_intr),
	DEVMETHOD(bus_teardown_intr,	vga_pci_teardown_intr),
	DEVMETHOD(bus_alloc_resource,	vga_pci_alloc_resource),
	DEVMETHOD(bus_release_resource,	vga_pci_release_resource),
	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
	DEVMETHOD(bus_get_dma_tag,	vga_pci_get_dma_tag),

	/* PCI interface */
	DEVMETHOD(pci_read_config,	vga_pci_read_config),
	DEVMETHOD(pci_write_config,	vga_pci_write_config),
	DEVMETHOD(pci_enable_busmaster,	vga_pci_enable_busmaster),
	DEVMETHOD(pci_disable_busmaster, vga_pci_disable_busmaster),
	DEVMETHOD(pci_enable_io,	vga_pci_enable_io),
	DEVMETHOD(pci_disable_io,	vga_pci_disable_io),
	DEVMETHOD(pci_get_vpd_ident,	vga_pci_get_vpd_ident),
	DEVMETHOD(pci_get_vpd_readonly,	vga_pci_get_vpd_readonly),
	DEVMETHOD(pci_get_powerstate,	vga_pci_get_powerstate),
	DEVMETHOD(pci_set_powerstate,	vga_pci_set_powerstate),
	DEVMETHOD(pci_assign_interrupt,	vga_pci_assign_interrupt),
	DEVMETHOD(pci_find_cap,		vga_pci_find_cap),
	DEVMETHOD(pci_find_next_cap,	vga_pci_find_next_cap),
	DEVMETHOD(pci_find_extcap,	vga_pci_find_extcap),
	DEVMETHOD(pci_find_next_extcap,	vga_pci_find_next_extcap),
	DEVMETHOD(pci_find_htcap,	vga_pci_find_htcap),
	DEVMETHOD(pci_find_next_htcap,	vga_pci_find_next_htcap),
	DEVMETHOD(pci_alloc_msi,	vga_pci_alloc_msi),
	DEVMETHOD(pci_alloc_msix,	vga_pci_alloc_msix),
	DEVMETHOD(pci_remap_msix,	vga_pci_remap_msix),
	DEVMETHOD(pci_release_msi,	vga_pci_release_msi),
	DEVMETHOD(pci_msi_count,	vga_pci_msi_count),
	DEVMETHOD(pci_msix_count,	vga_pci_msix_count),
	{ 0, 0 }
};

static driver_t vga_pci_driver = {
	"vgapci",
	vga_pci_methods,
	sizeof(struct vga_pci_softc),
};

DRIVER_MODULE(vgapci, pci, vga_pci_driver, 0, 0);
MODULE_DEPEND(vgapci, x86bios, 1, 1, 1);