drm/radeon: Add early unregister of firmware fb's

Without this, we attempt the handover too late, the firmware fb
might be accessing the chip simultaneously to us re-initializing
various parts of it, which might frighten babies or cause all sort
of nasty psychologic trauma to kitten.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[danvet: add cc: stable, forward ported and compile-fixed for X86]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[airlied: move to even earlier in module load.]
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_drv.c

@@ -232,9 +232,28 @@ static struct drm_driver driver_old = {
 
 static struct drm_driver kms_driver;
 
+static void radeon_kick_out_firmware_fb(struct pci_dev *pdev)
+{
+	struct apertures_struct *ap;
+	bool primary = false;
+
+	ap = alloc_apertures(1);
+	ap->ranges[0].base = pci_resource_start(pdev, 0);
+	ap->ranges[0].size = pci_resource_len(pdev, 0);
+
+#ifdef CONFIG_X86
+	primary = pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW;
+#endif
+	remove_conflicting_framebuffers(ap, "radeondrmfb", primary);
+	kfree(ap);
+}
+
 static int __devinit
 radeon_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
+	/* Get rid of things like offb */
+	radeon_kick_out_firmware_fb(pdev);
+
 	return drm_get_pci_dev(pdev, ent, &kms_driver);
 }