Patch "drm/dp/mst: Check peer device type before attempting EDID read" has been added to the 4.8-stable tree

Patch "drm/dp/mst: Check peer device type before attempting EDID read" has been added to the 4.8-stable tree

[gregkh]

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 4.8-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-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>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: 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@linux.intel.com>

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@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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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
@@ -1160,7 +1160,9 @@ 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@linux.intel.com are

queue-4.8/drm-release-reference-from-blob-lookup-after-replacing-property.patch
queue-4.8/x86-smpboot-init-apic-mapping-before-usage.patch
queue-4.8/drm-fb-helper-don-t-call-dirty-callback-for-untouched-clips.patch
queue-4.8/usb-gadget-function-u_ether-don-t-starve-tx-request-queue.patch
queue-4.8/drm-i915-clean-up-ddi-ddc-aux-ch-sanitation.patch
queue-4.8/drm-i915-respect-alternate_aux_channel-for-all-ddi-ports.patch
queue-4.8/drm-dp-mst-check-peer-device-type-before-attempting-edid-read.patch
queue-4.8/drm-fb-helper-keep-references-for-the-current-set-of-used-connectors.patch
queue-4.8/drm-dp-mst-clear-port-pdt-when-tearing-down-the-i2c-adapter.patch
queue-4.8/drm-fb-helper-fix-connector-ref-leak-on-error.patch
queue-4.8/drm-i915-fbc-fix-cfb-size-calculation-for-gen8.patch