1 files changed, 35 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/files/0475-drm-amdgpu-Don-t-link-train-DisplayPort-on-HPD-until.patch b/common/recipes-kernel/linux/files/0475-drm-amdgpu-Don-t-link-train-DisplayPort-on-HPD-until.patch
new file mode 100644
index 00000000..58c3be1a
--- /dev/null
+++ b/common/recipes-kernel/linux/files/0475-drm-amdgpu-Don-t-link-train-DisplayPort-on-HPD-until.patch
@@ -0,0 +1,35 @@
+From a887adadb7b9ef9eb4ee48e4ad575aefcfd1db14 Mon Sep 17 00:00:00 2001
+From: Alex Deucher <alexander.deucher@amd.com>
+Date: Fri, 21 Aug 2015 18:07:38 -0400
+Subject: [PATCH 0475/1050] drm/amdgpu: Don't link train DisplayPort on HPD
+ until we get the dpcd
+
+This is a port of:
+DRM - radeon: Don't link train DisplayPort on HPD until we get the dpcd
+to amdgpu.
+
+Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
+Cc: stable@vger.kernel.org
+---
+ drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+index 27df17a..89c3dd6 100644
+--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
++++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+@@ -75,6 +75,11 @@ void amdgpu_connector_hotplug(struct drm_connector *connector)
+ 			if (!amdgpu_display_hpd_sense(adev, amdgpu_connector->hpd.hpd)) {
+ 				drm_helper_connector_dpms(connector, DRM_MODE_DPMS_OFF);
+ 			} else if (amdgpu_atombios_dp_needs_link_train(amdgpu_connector)) {
++				/* Don't try to start link training before we
++				 * have the dpcd */
++				if (!amdgpu_atombios_dp_get_dpcd(amdgpu_connector))
++					return;
++
+ 				/* set it to OFF so that drm_helper_connector_dpms()
+ 				 * won't return immediately since the current state
+ 				 * is ON at this point.
+-- 
+1.9.1
+