drm: add test for AGP devices and driver override for it.

Added device_is_agp callback to drm_driver.  This function is called by the
platform-specific drm_device_is_agp function.  Added implementation of this
function the the Linux-specific portion of the MGA driver to detect PCI G450
cards.  Added code to the Linux-specific portion of the generic DRM layer to
not initialize AGP infrastructure if the card is not AGP (this matches what
already existed in BSD).

Fix up i810/i830 and i915 drivers to always return AGP as they don't always
report the capability.

Fix the MGA to not report AGP for a card that has an AGP chip behind a PCI
bridge.

From: Ian Romanick, Dave Airlie, Alan Hourihane
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/char/drm/i830_dma.c b/drivers/char/drm/i830_dma.c
index dc773303586..80d8966397c 100644
--- a/drivers/char/drm/i830_dma.c
+++ b/drivers/char/drm/i830_dma.c
@@ -1586,3 +1586,19 @@ drm_ioctl_desc_t i830_ioctls[] = {
 };
 
 int i830_max_ioctl = DRM_ARRAY_SIZE(i830_ioctls);
+
+/**
+ * Determine if the device really is AGP or not.
+ *
+ * All Intel graphics chipsets are treated as AGP, even if they are really
+ * PCI-e.
+ *
+ * \param dev   The device to be tested.
+ *
+ * \returns
+ * A value of 1 is always retured to indictate every i8xx is AGP.
+ */
+int i830_driver_device_is_agp(drm_device_t * dev)
+{
+        return 1;
+}