Fix AGP support guessing: Implement the same bridge checking in the MGA

    driver as Linux uses, and actually use the driver's device_is_agp if
    available (hopefully fixing i915).

2 files changed, 25 insertions, 1 deletions

diff --git a/bsd-core/drm_agpsupport.c b/bsd-core/drm_agpsupport.c
index 58293566..0a565105 100644
--- a/bsd-core/drm_agpsupport.c
+++ b/bsd-core/drm_agpsupport.c
@@ -89,6 +89,17 @@ drm_device_find_capability(drm_device_t *dev, int cap)
 
 int drm_device_is_agp(drm_device_t *dev)
 {
+	if (dev->driver.device_is_agp != NULL) {
+		int ret;
+
+		/* device_is_agp returns a tristate, 0 = not AGP, 1 = definitely
+		 * AGP, 2 = fall back to PCI capability
+		 */
+		ret = (*dev->driver.device_is_agp)(dev);
+		if (ret != 2)
+			return ret;
+	}
+
 	return (drm_device_find_capability(dev, PCIY_AGP));
 }
 
diff --git a/bsd-core/mga_drv.c b/bsd-core/mga_drv.c
index b3c8345b..1dc146f6 100644
--- a/bsd-core/mga_drv.c
+++ b/bsd-core/mga_drv.c
@@ -61,7 +61,20 @@ static drm_pci_id_list_t mga_pciidlist[] = {
  */
 static int mga_driver_device_is_agp(drm_device_t * dev)
 {
-	return 1;
+	/* There are PCI versions of the G450.  These cards have the
+	 * same PCI ID as the AGP G450, but have an additional PCI-to-PCI
+	 * bridge chip.  We detect these cards, which are not currently
+	 * supported by this driver, by looking at the device ID of the
+	 * bus the "card" is on.  If vendor is 0x3388 (Hint Corp) and the
+	 * device is 0x0021 (HB6 Universal PCI-PCI bridge), we reject the
+	 * device.
+	 */
+	if (pci_get_device(dev->device) == 0x0525 &&
+	    pci_get_vendor(device_get_parent(dev->device)) == 0x3388 &&
+	    pci_get_device(device_get_parent(dev->device)) == 0x0021)
+		return 0;
+	else
+		return 2;
 }
 
 static void mga_configure(drm_device_t *dev)