The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

2f3a1273862c ("drm/display/dp_mst: Fix drm_dp_mst_add_affected_dsc_crtcs() return code")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2f3a1273862cb82cca227630cc7f04ce0c94b6bb Mon Sep 17 00:00:00 2001 From: Lyude Paul lyude@redhat.com Date: Mon, 14 Nov 2022 17:17:53 -0500 Subject: [PATCH] drm/display/dp_mst: Fix drm_dp_mst_add_affected_dsc_crtcs() return code

Looks like that we're accidentally dropping a pretty important return code here. For some reason, we just return -EINVAL if we fail to get the MST topology state. This is wrong: error codes are important and should never be squashed without being handled, which here seems to have the potential to cause a deadlock.

Signed-off-by: Lyude Paul lyude@redhat.com Reviewed-by: Wayne Lin Wayne.Lin@amd.com Fixes: 8ec046716ca8 ("drm/dp_mst: Add helper to trigger modeset on affected DSC MST CRTCs") Cc: stable@vger.kernel.org # v5.6+ Signed-off-by: Alex Deucher alexander.deucher@amd.com

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index ecd22c038c8c..51a46689cda7 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -5186,7 +5186,7 @@ int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm mst_state = drm_atomic_get_mst_topology_state(state, mgr);

if (IS_ERR(mst_state)) - return -EINVAL; + return PTR_ERR(mst_state);

list_for_each_entry(pos, &mst_state->payloads, next) {