drm/dp_mst: Don't return error code when crtc is null

commit 88fee1c9007a38c19f2c558dc0ab1ddb4c323dc5 upstream.

[Why]
In certain cases the crtc can be NULL and returning -EINVAL causes
atomic check to fail when it shouln't. This leads to valid
configurations failing because atomic check fails.

[How]
Don't early return if crtc is null

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[added stable cc]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 8ec046716ca8 ("drm/dp_mst: Add helper to trigger modeset on affected DSC MST CRTCs")
Cc: <stable@vger.kernel.org> # v5.6+
Link: https://patchwork.freedesktop.org/patch/msgid/20200814170140.24917-1-Bhawanpreet.Lakha@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index ffbd754a5382559234dae369b429d2f57d4bd6a6..954cd69117826623b7f8ed8cdfe66dc5d99e7057 100644 (file)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -4993,8 +4993,8 @@ int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm
 
                crtc = conn_state->crtc;
 
-               if (WARN_ON(!crtc))
-                       return -EINVAL;
+               if (!crtc)
+                       continue;
 
                if (!drm_dp_mst_dsc_aux_for_port(pos->port))
                        continue;