[PATCH] drm/i915: prevent generating unusable gvt build which no mpt module is selected

[changbin.du at intel.com]

From: Changbin Du <changbin.du at intel.com>

At least we need one MPT module (currently only have one) selected
to get GVTg functional. When GVTg is enabled while no MPT selected,
the build just includes useless GVTg code. This doesn't make sense.

With this patch, a submenut is created under i915 as below:
  -*- Enable Intel GVT-g graphics virtualization host support
  <M> Enable KVM/VFIO support for Intel GVT-g

If no MPT is selected, GVTg will be disabled automatically.
  < > Enable KVM/VFIO support for Intel GVT-g

Signed-off-by: Changbin Du <changbin.du at intel.com>
---
 drivers/gpu/drm/i915/Kconfig | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index a5cd5da..e380a5d 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -91,12 +91,15 @@ config DRM_I915_USERPTR
 
 	  If in doubt, say "Y".
 
+menu "Intel GVT-g graphics virtualization host support"
+	depends on DRM_I915
+	depends on 64BIT
+
 config DRM_I915_GVT
-        bool "Enable Intel GVT-g graphics virtualization host support"
-        depends on DRM_I915
-        depends on 64BIT
-        default n
-        help
+	bool "Enable Intel GVT-g graphics virtualization host support"
+	default n
+	depends on DRM_I915_GVT_KVMGT
+	help
 	  Choose this option if you want to enable Intel GVT-g graphics
 	  virtualization technology host support with integrated graphics.
 	  With GVT-g, it's possible to have one integrated graphics
@@ -116,13 +119,14 @@ config DRM_I915_GVT
 
 config DRM_I915_GVT_KVMGT
 	tristate "Enable KVM/VFIO support for Intel GVT-g"
-	depends on DRM_I915_GVT
+	select DRM_I915_GVT
 	depends on KVM
 	depends on VFIO_MDEV && VFIO_MDEV_DEVICE
 	default n
 	help
 	  Choose this option if you want to enable KVMGT support for
 	  Intel GVT-g.
+endmenu
 
 menu "drm/i915 Debugging"
 depends on DRM_I915
-- 
2.7.4