drm/amdgpu: fix vega10 graphic hang issue in S3 test

mmVGT_INDEX_TYPE has no default value, need to make sure
it's initialized when gfx is initialized.
Signed-off-by: Ken Wang <Ken.Wang@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c

@@ -2157,7 +2157,7 @@ static int gfx_v9_0_cp_gfx_start(struct amdgpu_device *adev)
 	struct amdgpu_ring *ring = &adev->gfx.gfx_ring[0];
 	const struct cs_section_def *sect = NULL;
 	const struct cs_extent_def *ext = NULL;
-	int r, i;
+	int r, i, tmp;
 
 	/* init the CP */
 	WREG32_SOC15(GC, 0, mmCP_MAX_CONTEXT, adev->gfx.config.max_hw_contexts - 1);
@@ -2165,7 +2165,7 @@ static int gfx_v9_0_cp_gfx_start(struct amdgpu_device *adev)
 
 	gfx_v9_0_cp_gfx_enable(adev, true);
 
-	r = amdgpu_ring_alloc(ring, gfx_v9_0_get_csb_size(adev) + 4);
+	r = amdgpu_ring_alloc(ring, gfx_v9_0_get_csb_size(adev) + 4 + 3);
 	if (r) {
 		DRM_ERROR("amdgpu: cp failed to lock ring (%d).\n", r);
 		return r;
@@ -2203,6 +2203,12 @@ static int gfx_v9_0_cp_gfx_start(struct amdgpu_device *adev)
 	amdgpu_ring_write(ring, 0x8000);
 	amdgpu_ring_write(ring, 0x8000);
 
+	amdgpu_ring_write(ring, PACKET3(PACKET3_SET_UCONFIG_REG,1));
+	tmp = (PACKET3_SET_UCONFIG_REG_INDEX_TYPE |
+		(SOC15_REG_OFFSET(GC, 0, mmVGT_INDEX_TYPE) - PACKET3_SET_UCONFIG_REG_START));
+	amdgpu_ring_write(ring, tmp);
+	amdgpu_ring_write(ring, 0);
+
 	amdgpu_ring_commit(ring);
 
 	return 0;

drivers/gpu/drm/amd/amdgpu/soc15d.h

@@ -250,6 +250,7 @@
 #define	PACKET3_SET_UCONFIG_REG				0x79
 #define		PACKET3_SET_UCONFIG_REG_START			0x0000c000
 #define		PACKET3_SET_UCONFIG_REG_END			0x0000c400
+#define		PACKET3_SET_UCONFIG_REG_INDEX_TYPE		(2 << 28)
 #define	PACKET3_SCRATCH_RAM_WRITE			0x7D
 #define	PACKET3_SCRATCH_RAM_READ			0x7E
 #define	PACKET3_LOAD_CONST_RAM				0x80