drm/amdgpu: add warning for GRBM 1-cycle delay issue in gfx9

It needs to add warning to update firmware in gfx9
in case that firmware is too old to have function to
realize dummy read in cp firmware.

Signed-off-by: changzhu <Changfeng.Zhu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -973,6 +973,13 @@ static void gfx_v9_0_check_fw_write_wait(struct amdgpu_device *adev)
 	adev->gfx.me_fw_write_wait = false;
 	adev->gfx.mec_fw_write_wait = false;
 
+	if ((adev->gfx.mec_fw_version < 0x000001a5) ||
+	    (adev->gfx.mec_feature_version < 46) ||
+	    (adev->gfx.pfp_fw_version < 0x000000b7) ||
+	    (adev->gfx.pfp_feature_version < 46))
+		DRM_WARN_ONCE("Warning: check cp_fw_version and update it to realize \
+			      GRBM requires 1-cycle delay in cp firmware\n");
+
 	switch (adev->asic_type) {
 	case CHIP_VEGA10:
 		if ((adev->gfx.me_fw_version >= 0x0000009c) &&