This is a note to let you know that I've just added the patch titled drm/dp/mst: Check peer device type before attempting EDID read to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-dp-mst-check-peer-device-type-before-attempting-edid-read.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4da5caa6a6f82cda3193bca855235b87debf78bd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@xxxxxxxxxxxxxxx> Date: Wed, 26 Oct 2016 12:05:55 +0300 Subject: 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 From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> commit 4da5caa6a6f82cda3193bca855235b87debf78bd upstream. 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: Carlos Santa <carlos.santa@xxxxxxxxx> Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> Tested-by: Carlos Santa <carlos.santa@xxxxxxxxx> Tested-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97666 Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Link: http://patchwork.freedesktop.org/patch/msgid/1477472755-15288-5-git-send-email-ville.syrjala@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/drm_dp_mst_topology.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -1155,7 +1155,9 @@ static void drm_dp_add_port(struct drm_d 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); } Patches currently in stable-queue which might be from ville.syrjala@xxxxxxxxxxxxxxx are queue-4.4/usb-gadget-function-u_ether-don-t-starve-tx-request-queue.patch queue-4.4/drm-i915-clean-up-ddi-ddc-aux-ch-sanitation.patch queue-4.4/drm-dp-mst-check-peer-device-type-before-attempting-edid-read.patch queue-4.4/drm-fb-helper-keep-references-for-the-current-set-of-used-connectors.patch queue-4.4/drm-dp-mst-clear-port-pdt-when-tearing-down-the-i2c-adapter.patch queue-4.4/drm-fb-helper-fix-connector-ref-leak-on-error.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html