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>

drivers/char/drm/drmP.h

@@ -586,7 +586,22 @@ struct drm_driver {
  	int (*kernel_context_switch)(struct drm_device *dev, int old, int new);
 	void (*kernel_context_switch_unlock)(struct drm_device *dev, drm_lock_t *lock);
 	int (*vblank_wait)(struct drm_device *dev, unsigned int *sequence);
+
+	/**
+	 * Called by \c drm_device_is_agp.  Typically used to determine if a
+	 * card is really attached to AGP or not.
+	 *
+	 * \param dev  DRM device handle
+	 *
+	 * \returns
+	 * One of three values is returned depending on whether or not the
+	 * card is absolutely \b not AGP (return of 0), absolutely \b is AGP
+	 * (return of 1), or may or may not be AGP (return of 2).
+	 */
+	int (*device_is_agp) (struct drm_device * dev);
+
 	/* these have to be filled in */
+
  	int (*postinit)(struct drm_device *, unsigned long flags);
 	irqreturn_t (*irq_handler)( DRM_IRQ_ARGS );
  	void (*irq_preinstall)(struct drm_device *dev);
@@ -1041,6 +1056,19 @@ static __inline__ struct drm_map *drm_core_findmap(struct drm_device *dev, unsig
 	return NULL;
 }
 
+static __inline__ int drm_device_is_agp(drm_device_t *dev)
+{
+	if ( dev->driver->device_is_agp != NULL ) {
+		int err = (*dev->driver->device_is_agp)( dev );
+
+		if (err != 2) {
+			return err;
+		}
+	}
+
+	return pci_find_capability(dev->pdev, PCI_CAP_ID_AGP);
+}
+
 static __inline__ void drm_core_dropmap(struct drm_map *map)
 {
 }

drivers/char/drm/drm_stub.c

@@ -91,7 +91,8 @@ static int drm_fill_in_dev(drm_device_t *dev, struct pci_dev *pdev, const struct
 			goto error_out_unreg;
 
 	if (drm_core_has_AGP(dev)) {
-		dev->agp = drm_agp_init(dev);
+		if (drm_device_is_agp(dev))
+			dev->agp = drm_agp_init(dev);
 		if (drm_core_check_feature(dev, DRIVER_REQUIRE_AGP) && (dev->agp == NULL)) {
 			DRM_ERROR( "Cannot initialize the agpgart module.\n" );
 			retcode = -EINVAL;

drivers/char/drm/i810_dma.c

@@ -1383,3 +1383,19 @@ drm_ioctl_desc_t i810_ioctls[] = {
 };
 
 int i810_max_ioctl = DRM_ARRAY_SIZE(i810_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 i810 is AGP.
+ */
+int i810_driver_device_is_agp(drm_device_t * dev)
+{
+	return 1;
+}

drivers/char/drm/i810_drv.c

@@ -84,6 +84,7 @@ static struct drm_driver driver = {
 	.dev_priv_size = sizeof(drm_i810_buf_priv_t),
 	.pretakedown = i810_driver_pretakedown,
 	.prerelease = i810_driver_prerelease,
+	.device_is_agp = i810_driver_device_is_agp,
 	.release = i810_driver_release,
 	.dma_quiescent = i810_driver_dma_quiescent,
 	.reclaim_buffers = i810_reclaim_buffers,

drivers/char/drm/i810_drv.h

@@ -120,6 +120,7 @@ extern int i810_driver_dma_quiescent(drm_device_t *dev);
 extern void i810_driver_release(drm_device_t *dev, struct file *filp);
 extern void i810_driver_pretakedown(drm_device_t *dev);
 extern void i810_driver_prerelease(drm_device_t *dev, DRMFILE filp);
+extern int i810_driver_device_is_agp(drm_device_t * dev);
 
 #define I810_BASE(reg)		((unsigned long) \
 				dev_priv->mmio_map->handle)

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;
+}

drivers/char/drm/i830_drv.c

@@ -88,6 +88,7 @@ static struct drm_driver driver = {
 	.dev_priv_size = sizeof(drm_i830_buf_priv_t),
 	.pretakedown = i830_driver_pretakedown,
 	.prerelease = i830_driver_prerelease,
+	.device_is_agp = i830_driver_device_is_agp,
 	.release = i830_driver_release,
 	.dma_quiescent = i830_driver_dma_quiescent,
 	.reclaim_buffers = i830_reclaim_buffers,

drivers/char/drm/i830_drv.h

@@ -137,6 +137,7 @@ extern void i830_driver_pretakedown(drm_device_t *dev);
 extern void i830_driver_release(drm_device_t *dev, struct file *filp);
 extern int i830_driver_dma_quiescent(drm_device_t *dev);
 extern void i830_driver_prerelease(drm_device_t *dev, DRMFILE filp);
+extern int i830_driver_device_is_agp(drm_device_t * dev);
 
 #define I830_BASE(reg)		((unsigned long) \
 				dev_priv->mmio_map->handle)

drivers/char/drm/i915_dma.c

@@ -732,3 +732,19 @@ drm_ioctl_desc_t i915_ioctls[] = {
 };
 
 int i915_max_ioctl = DRM_ARRAY_SIZE(i915_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 i9x5 is AGP.
+ */
+int i915_driver_device_is_agp(drm_device_t * dev)
+{
+	return 1;
+}

drivers/char/drm/i915_drv.c

@@ -79,6 +79,7 @@ static struct drm_driver driver = {
 				DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED,
 	.pretakedown = i915_driver_pretakedown,
 	.prerelease = i915_driver_prerelease,
+	.device_is_agp = i915_driver_device_is_agp,
 	.irq_preinstall = i915_driver_irq_preinstall,
 	.irq_postinstall = i915_driver_irq_postinstall,
 	.irq_uninstall = i915_driver_irq_uninstall,

drivers/char/drm/i915_drv.h

@@ -103,6 +103,7 @@ typedef struct drm_i915_private {
 extern void i915_kernel_lost_context(drm_device_t * dev);
 extern void i915_driver_pretakedown(drm_device_t *dev);
 extern void i915_driver_prerelease(drm_device_t *dev, DRMFILE filp);
+extern int i915_driver_device_is_agp(drm_device_t *dev);
 
 /* i915_irq.c */
 extern int i915_irq_emit(DRM_IOCTL_ARGS);

drivers/char/drm/mga_drv.c

@@ -38,6 +38,7 @@
 
 #include "drm_pciids.h"
 
+static int mga_driver_device_is_agp(drm_device_t * dev);
 static int postinit( struct drm_device *dev, unsigned long flags )
 {
 	dev->counters += 3;
@@ -81,6 +82,7 @@ static struct drm_driver driver = {
 	.driver_features = DRIVER_USE_AGP | DRIVER_REQUIRE_AGP | DRIVER_USE_MTRR | DRIVER_HAVE_DMA | DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_IRQ_VBL,
 	.pretakedown = mga_driver_pretakedown,
 	.dma_quiescent = mga_driver_dma_quiescent,
+	.device_is_agp = mga_driver_device_is_agp,
 	.vblank_wait = mga_driver_vblank_wait,
 	.irq_preinstall = mga_driver_irq_preinstall,
 	.irq_postinstall = mga_driver_irq_postinstall,
@@ -128,3 +130,38 @@ module_exit(mga_exit);
 MODULE_AUTHOR( DRIVER_AUTHOR );
 MODULE_DESCRIPTION( DRIVER_DESC );
 MODULE_LICENSE("GPL and additional rights");
+
+/**
+ * Determine if the device really is AGP or not.
+ *
+ * In addition to the usual tests performed by \c drm_device_is_agp, this
+ * function detects PCI G450 cards that appear to the system exactly like
+ * AGP G450 cards.
+ *
+ * \param dev   The device to be tested.
+ *
+ * \returns
+ * If the device is a PCI G450, zero is returned.  Otherwise 2 is returned.
+ */
+int mga_driver_device_is_agp(drm_device_t * dev)
+{
+	const struct pci_dev * const pdev = dev->pdev;
+
+
+	/* 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 ( (pdev->device == 0x0525)
+	     && (pdev->bus->self->vendor == 0x3388)
+	     && (pdev->bus->self->device == 0x0021) ) {
+		return 0;
+	}
+
+	return 2;
+}

drivers/char/drm/mga_drv.h

@@ -38,11 +38,11 @@
 
 #define DRIVER_NAME		"mga"
 #define DRIVER_DESC		"Matrox G200/G400"
-#define DRIVER_DATE		"20021029"
+#define DRIVER_DATE		"20051013"
 
 #define DRIVER_MAJOR		3
 #define DRIVER_MINOR		1
-#define DRIVER_PATCHLEVEL	0
+#define DRIVER_PATCHLEVEL	1
 
 typedef struct drm_mga_primary_buffer {
 	u8 *start;