drm/amdgpu: create amdgpu_vkms

Modify the VKMS driver into an api that dce_virtual can use to create
virtual displays that obey drm's atomic modesetting api.

Signed-off-by: Ryan Taylor <Ryan.Taylor@amd.com>

drivers/gpu/drm/amd/amdgpu/Makefile

@@ -119,6 +119,7 @@ amdgpu-y += \
 amdgpu-y += \
 	dce_v10_0.o \
 	dce_v11_0.o \
+	amdgpu_vkms.o \
 	dce_virtual.o
 
 # add GFX block

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -909,6 +909,7 @@ struct amdgpu_device {
 
 	/* display */
 	bool				enable_virtual_display;
+	struct amdgpu_vkms_output       *amdgpu_vkms_output;
 	struct amdgpu_mode_info		mode_info;
 	/* For pre-DCE11. DCE11 and later are in "struct amdgpu_device->dm" */
 	struct work_struct		hotplug_work;

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -1223,7 +1223,7 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 	int ret, retry = 0;
 	bool supports_atomic = false;
 
-	if (!amdgpu_virtual_display &&
+	if (amdgpu_virtual_display ||
 	    amdgpu_device_asic_has_dc_support(flags & AMD_ASIC_MASK))
 		supports_atomic = true;
 

drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c

@@ -344,7 +344,7 @@ int amdgpu_fbdev_init(struct amdgpu_device *adev)
 	}
 
 	/* disable all the possible outputs/crtcs before entering KMS mode */
-	if (!amdgpu_device_has_dc_support(adev))
+	if (!amdgpu_device_has_dc_support(adev) && !amdgpu_virtual_display)
 		drm_helper_disable_unused_functions(adev_to_drm(adev));
 
 	drm_fb_helper_initial_config(&rfbdev->helper, bpp_sel);