From 4da5caa6a6f82cda3193bca855235b87debf78bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Wed, 26 Oct 2016 12:05:55 +0300
Subject: [PATCH] drm/dp/mst: Check peer device type before attempting EDID
read
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Only certain types of pdts have the DDC bus registered, so check for
that before we attempt the EDID read. Othwewise we risk playing around
with an i2c adapter that doesn't actually exist.
Cc: stable@vger.kernel.org
Cc: Carlos Santa <carlos.santa@intel.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Tested-by: Carlos Santa <carlos.santa@intel.com>
Tested-by: Kirill A. Shutemov <kirill@shutemov.name>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97666
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1477472755-15288-5-git-send-email-ville.syrjala@linux.intel.com
---
drivers/gpu/drm/drm_dp_mst_topology.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index ba13f9d8720b..aa644487749c 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1160,7 +1160,9 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
drm_dp_put_port(port);
goto out;
}
- if (port->port_num >= DP_MST_LOGICAL_PORT_0) {
+ if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||
+ port->pdt == DP_PEER_DEVICE_SST_SINK) &&
+ port->port_num >= DP_MST_LOGICAL_PORT_0) {
port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
drm_mode_connector_set_tile_property(port->connector);
}
--
GitLab