[PATCH] drm/amd: Fail initialization earlier when DC is disabled

[Mario Limonciello]

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.limonciello at 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