drm/radeon: don't probe MST on hw we don't support it on

If you do radeon.mst=1 on a gpu without mst hw, and then
plug some mst hw it will oops instead of falling back.

So check we have DCE5 at least before proceeding.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Christian König <christian.koenig@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_dp_mst.c b/drivers/gpu/drm/radeon/radeon_dp_mst.c
index 2b98ed3e684d706a07e3c43b6da9f2232143e580..257b10be5cda902861339d9fde17c38e4f238d06 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_dp_mst.c
+++ b/drivers/gpu/drm/radeon/radeon_dp_mst.c
@@ -663,12 +663,17 @@ int
 radeon_dp_mst_probe(struct radeon_connector *radeon_connector)
 {
        struct radeon_connector_atom_dig *dig_connector = radeon_connector->con_priv;
+       struct drm_device *dev = radeon_connector->base.dev;
+       struct radeon_device *rdev = dev->dev_private;
        int ret;
        u8 msg[1];
 
        if (!radeon_mst)
                return 0;
 
+       if (!ASIC_IS_DCE5(rdev))
+               return 0;
+
        if (dig_connector->dpcd[DP_DPCD_REV] < 0x12)
                return 0;