drm/amdgpu: Enable CP idle interrupts

v1: The interrupts need to be enabled to move to DS clocks.
v2: Don't enable GFX IDLE interrupts if there are no GFX rings.
Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -2669,17 +2669,15 @@ static void gfx_v9_0_enable_gui_idle_interrupt(struct amdgpu_device *adev,
 {
 	u32 tmp;
 
-	/* don't toggle interrupts that are only applicable
-	 * to me0 pipe0 on AISCs that have me0 removed */
-	if (!adev->gfx.num_gfx_rings)
-		return;
+	/* These interrupts should be enabled to drive DS clock */
 
 	tmp= RREG32_SOC15(GC, 0, mmCP_INT_CNTL_RING0);
 
 	tmp = REG_SET_FIELD(tmp, CP_INT_CNTL_RING0, CNTX_BUSY_INT_ENABLE, enable ? 1 : 0);
 	tmp = REG_SET_FIELD(tmp, CP_INT_CNTL_RING0, CNTX_EMPTY_INT_ENABLE, enable ? 1 : 0);
 	tmp = REG_SET_FIELD(tmp, CP_INT_CNTL_RING0, CMP_BUSY_INT_ENABLE, enable ? 1 : 0);
-	tmp = REG_SET_FIELD(tmp, CP_INT_CNTL_RING0, GFX_IDLE_INT_ENABLE, enable ? 1 : 0);
+	if(adev->gfx.num_gfx_rings)
+		tmp = REG_SET_FIELD(tmp, CP_INT_CNTL_RING0, GFX_IDLE_INT_ENABLE, enable ? 1 : 0);
 
 	WREG32_SOC15(GC, 0, mmCP_INT_CNTL_RING0, tmp);
 }