[Intel-gfx] [PATCH] drm/i915: fix dependence for intel agp module

[Zhenyu Wang]

See http://bugzilla.kernel.org/show_bug.cgi?id=15021

This one trys to ensure the module dependence with drm/i915
on intel_agp module by using a exported symbol. Because intel_agp
is a subdriver for agp, so the required dependence isn't built
with i915 subdriver for drm. I hope this is not too strange..

Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
---
 drivers/char/agp/intel-agp.c    |   10 ++++++++--
 drivers/gpu/drm/i915/i915_drv.c |    6 ++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
index e5ffefe..c921ee2 100644
--- a/drivers/char/agp/intel-agp.c
+++ b/drivers/char/agp/intel-agp.c
@@ -10,6 +10,9 @@
 #include <linux/agp_backend.h>
 #include "agp.h"
 
+int intel_agp_enabled;
+EXPORT_SYMBOL(intel_agp_enabled);
+
 /*
  * If we have Intel graphics, we're not going to have anything other than
  * an Intel IOMMU. So make the correct use of the PCI DMA API contingent
@@ -2378,7 +2381,7 @@ static int __devinit agp_intel_probe(struct pci_dev *pdev,
 	struct agp_bridge_data *bridge;
 	u8 cap_ptr = 0;
 	struct resource *r;
-	int i;
+	int i, err;
 
 	cap_ptr = pci_find_capability(pdev, PCI_CAP_ID_AGP);
 
@@ -2470,7 +2473,10 @@ static int __devinit agp_intel_probe(struct pci_dev *pdev,
 	}
 
 	pci_set_drvdata(pdev, bridge);
-	return agp_add_bridge(bridge);
+	err = agp_add_bridge(bridge);
+	if (!err)
+		intel_agp_enabled = 1;
+	return err;
 }
 
 static void __devexit agp_intel_remove(struct pci_dev *pdev)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index cf4cb3e..48ae2c2 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -49,6 +49,7 @@ unsigned int i915_lvds_downclock = 0;
 module_param_named(lvds_downclock, i915_lvds_downclock, int, 0400);
 
 static struct drm_driver driver;
+extern int intel_agp_enabled;
 
 #define INTEL_VGA_DEVICE(id, info) {		\
 	.class = PCI_CLASS_DISPLAY_VGA << 8,	\
@@ -546,6 +547,11 @@ static struct drm_driver driver = {
 
 static int __init i915_init(void)
 {
+	if (!intel_agp_enabled) {
+		DRM_ERROR("drm/i915 can't work without intel_agp module!\n");
+		return -ENODEV;
+	}
+
 	driver.num_ioctls = i915_max_ioctl;
 
 	i915_gem_shrinker_init();
-- 
1.6.3.3