Modern APU and dGPU require DC support to be able to light up the
display.  If DC support has been disabled either by kernel config
or by kernel command line fail init early so that the system won't
freeze with a lack of display.

Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 24 +++++++++++++++----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
index a4258127083d..c4e1505dcaac 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
@@ -2139,10 +2139,6 @@ static int amdgpu_discovery_set_display_ip_blocks(struct 
amdgpu_device *adev)
                return 0;
        }
 
-       if (!amdgpu_device_has_dc_support(adev))
-               return 0;
-
-#if defined(CONFIG_DRM_AMD_DC)
        if (amdgpu_ip_version(adev, DCE_HWIP, 0)) {
                switch (amdgpu_ip_version(adev, DCE_HWIP, 0)) {
                case IP_VERSION(1, 0, 0):
@@ -2166,15 +2162,24 @@ static int 
amdgpu_discovery_set_display_ip_blocks(struct amdgpu_device *adev)
                case IP_VERSION(3, 5, 1):
                case IP_VERSION(3, 6, 0):
                case IP_VERSION(4, 1, 0):
+                       if (!amdgpu_device_has_dc_support(adev)) {
+                               dev_err(adev->dev,
+                                       "DC support is required for dm ip 
block(DCE_HWIP:0x%x)\n",
+                                       amdgpu_ip_version(adev, DCE_HWIP, 0));
+                               return -EINVAL;
+                       }
+
                        /* TODO: Fix IP version. DC code expects version 4.0.1 
*/
                        if (adev->ip_versions[DCE_HWIP][0] == IP_VERSION(4, 1, 
0))
                                adev->ip_versions[DCE_HWIP][0] = IP_VERSION(4, 
0, 1);
 
+#if defined(CONFIG_DRM_AMD_DC)
                        if (amdgpu_sriov_vf(adev))
                                amdgpu_discovery_set_sriov_display(adev);
                        else
                                amdgpu_device_ip_block_add(adev, &dm_ip_block);
                        break;
+#endif
                default:
                        dev_err(adev->dev,
                                "Failed to add dm ip block(DCE_HWIP:0x%x)\n",
@@ -2186,11 +2191,21 @@ static int 
amdgpu_discovery_set_display_ip_blocks(struct amdgpu_device *adev)
                case IP_VERSION(12, 0, 0):
                case IP_VERSION(12, 0, 1):
                case IP_VERSION(12, 1, 0):
+
+               if (!amdgpu_device_has_dc_support(adev)) {
+                       dev_err(adev->dev,
+                               "DC support is required for dm ip 
block(DCI_HWIP:0x%x)\n",
+                               amdgpu_ip_version(adev, DCI_HWIP, 0));
+                       return -EINVAL;
+               }
+
+#if defined(CONFIG_DRM_AMD_DC)
                        if (amdgpu_sriov_vf(adev))
                                amdgpu_discovery_set_sriov_display(adev);
                        else
                                amdgpu_device_ip_block_add(adev, &dm_ip_block);
                        break;
+#endif
                default:
                        dev_err(adev->dev,
                                "Failed to add dm ip block(DCI_HWIP:0x%x)\n",
@@ -2198,7 +2213,6 @@ static int amdgpu_discovery_set_display_ip_blocks(struct 
amdgpu_device *adev)
                        return -EINVAL;
                }
        }
-#endif
        return 0;
 }
 
-- 
2.48.1

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