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From:   Lyude Paul <lyude@redhat.com>
To:     amd-gfx@lists.freedesktop.org
Cc:     Wayne Lin <Wayne.Lin@amd.com>, stable@vger.kernel.org,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jani Nikula <jani.nikula@intel.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Imre Deak <imre.deak@intel.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Mikita Lipski <mikita.lipski@amd.com>,
        dri-devel@lists.freedesktop.org (open list:DRM DRIVERS),
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v2 2/4] drm/display/dp_mst: Fix drm_dp_mst_add_affected_dsc_crtcs() return code
Date:   Mon, 14 Nov 2022 17:17:53 -0500
Message-Id: <20221114221754.385090-3-lyude@redhat.com>
In-Reply-To: <20221114221754.385090-1-lyude@redhat.com>
References: <20221114221754.385090-1-lyude@redhat.com>
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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+
---
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index ecd22c038c8c0..51a46689cda70 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) {
 
-- 
2.37.3