drm/i915: Kill legeacy AGP for gen3 kms

Thus far we've tried to carefully work around the fact that old
userspace relied on the AGP-backed legacy buffer mapping ioctls for a
bit too long. But it's really horribly, and now some new users for it
started to show up again:

http://www.mail-archive.com/mesa-dev@lists.freedesktop.org/msg45547.html

This uses drmAgpSize to figure out the GTT size, which is both the
wrong thing to inquire and also might force us to keep this crap
around for another few years.

So I want to stop this particular zombie from raising ever again. Now
it's only been 4 years since XvMC was fixed for gen3, so a bit early
by the usual rules. But since Linus explicitly said that an ABI
breakage only counts if someone actually observes it I want to tempt
fate an accelarate the demise of AGP.

We probably need to wait 2-3 kernel releases with this shipping until
we go on a killing spree code-wise.

v2: Remove intel_agp_enabled since it's unused (Ville).

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Dave Airlie <airlied@gmail.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/char/agp/intel-agp.c

@@ -14,9 +14,6 @@
 #include "intel-agp.h"
 #include <drm/intel-gtt.h>
 
-int intel_agp_enabled;
-EXPORT_SYMBOL(intel_agp_enabled);
-
 static int intel_fetch_size(void)
 {
 	int i;
@@ -814,8 +811,6 @@ static int agp_intel_probe(struct pci_dev *pdev,
 found_gmch:
 	pci_set_drvdata(pdev, bridge);
 	err = agp_add_bridge(bridge);
-	if (!err)
-		intel_agp_enabled = 1;
 	return err;
 }
 

drivers/gpu/drm/i915/i915_drv.c

@@ -155,11 +155,6 @@ MODULE_PARM_DESC(prefault_disable,
 		"Disable page prefaulting for pread/pwrite/reloc (default:false). For developers only.");
 
 static struct drm_driver driver;
-#if IS_ENABLED(CONFIG_AGP_INTEL)
-extern int intel_agp_enabled;
-#else
-static int intel_agp_enabled = 1;
-#endif
 
 static const struct intel_device_info intel_i830_info = {
 	.gen = 2, .is_mobile = 1, .cursor_needs_physical = 1, .num_pipes = 2,
@@ -797,17 +792,7 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (PCI_FUNC(pdev->devfn))
 		return -ENODEV;
 
-	/* We've managed to ship a kms-enabled ddx that shipped with an XvMC
-	 * implementation for gen3 (and only gen3) that used legacy drm maps
-	 * (gasp!) to share buffers between X and the client. Hence we need to
-	 * keep around the fake agp stuff for gen3, even when kms is enabled. */
-	if (intel_info->gen != 3) {
-		driver.driver_features &=
-			~(DRIVER_USE_AGP | DRIVER_REQUIRE_AGP);
-	} else if (!intel_agp_enabled) {
-		DRM_ERROR("drm/i915 can't work without intel_agp module!\n");
-		return -ENODEV;
-	}
+	driver.driver_features &= ~(DRIVER_USE_AGP | DRIVER_REQUIRE_AGP);
 
 	return drm_get_pci_dev(pdev, ent, &driver);
 }