linux-kernel - [PATCH 4.16 104/113] drm/amd/display: Dont read EDID in atomic

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Message-Id: <20180430184019.596757596@linuxfoundation.org>
Date:   Mon, 30 Apr 2018 12:25:15 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Harry Wentland <harry.wentland@....com>,
        Tony Cheng <Tony.Cheng@....com>,
        Alex Deucher <alexander.deucher@....com>
Subject: [PATCH 4.16 104/113] drm/amd/display: Dont read EDID in atomic_check

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Harry Wentland <harry.wentland@....com>

commit c7b8de00384be49dc1617a838b0ce89a0235f319 upstream.

We shouldn't attempt to read EDID in atomic_check. We really shouldn't
even be modifying the connector object, or any other non-state object,
but this is a start at least.

Moving EDID cleanup to dm_dp_mst_connector_destroy from
dm_dp_destroy_mst_connector to ensure the EDID is still available for
headless mode.

Signed-off-by: Harry Wentland <harry.wentland@....com>
Reviewed-by: Tony Cheng <Tony.Cheng@....com>
Acked-by: Harry Wentland <harry.wentland@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Cc: stable@...r.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c |   32 +++---------
 1 file changed, 10 insertions(+), 22 deletions(-)

--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -157,6 +157,11 @@ dm_dp_mst_connector_destroy(struct drm_c
 	struct amdgpu_dm_connector *amdgpu_dm_connector = to_amdgpu_dm_connector(connector);
 	struct amdgpu_encoder *amdgpu_encoder = amdgpu_dm_connector->mst_encoder;
 
+	if (amdgpu_dm_connector->edid) {
+		kfree(amdgpu_dm_connector->edid);
+		amdgpu_dm_connector->edid = NULL;
+	}
+
 	drm_encoder_cleanup(&amdgpu_encoder->base);
 	kfree(amdgpu_encoder);
 	drm_connector_cleanup(connector);
@@ -183,28 +188,22 @@ static int dm_connector_update_modes(str
 void dm_dp_mst_dc_sink_create(struct drm_connector *connector)
 {
 	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
-	struct edid *edid;
 	struct dc_sink *dc_sink;
 	struct dc_sink_init_data init_params = {
 			.link = aconnector->dc_link,
 			.sink_signal = SIGNAL_TYPE_DISPLAY_PORT_MST };
 
+	/* FIXME none of this is safe. we shouldn't touch aconnector here in
+	 * atomic_check
+	 */
+
 	/*
 	 * TODO: Need to further figure out why ddc.algo is NULL while MST port exists
 	 */
 	if (!aconnector->port || !aconnector->port->aux.ddc.algo)
 		return;
 
-	edid = drm_dp_mst_get_edid(connector, &aconnector->mst_port->mst_mgr, aconnector->port);
-
-	if (!edid) {
-		drm_mode_connector_update_edid_property(
-			&aconnector->base,
-			NULL);
-		return;
-	}
-
-	aconnector->edid = edid;
+	ASSERT(aconnector->edid);
 
 	dc_sink = dc_link_add_remote_sink(
 		aconnector->dc_link,
@@ -217,9 +216,6 @@ void dm_dp_mst_dc_sink_create(struct drm
 
 	amdgpu_dm_add_sink_to_freesync_module(
 			connector, aconnector->edid);
-
-	drm_mode_connector_update_edid_property(
-					&aconnector->base, aconnector->edid);
 }
 
 static int dm_dp_mst_get_modes(struct drm_connector *connector)
@@ -426,14 +422,6 @@ static void dm_dp_destroy_mst_connector(
 		dc_sink_release(aconnector->dc_sink);
 		aconnector->dc_sink = NULL;
 	}
-	if (aconnector->edid) {
-		kfree(aconnector->edid);
-		aconnector->edid = NULL;
-	}
-
-	drm_mode_connector_update_edid_property(
-			&aconnector->base,
-			NULL);
 
 	aconnector->mst_connected = false;
 }