Patch "drm/amdgpu: return from atombios_dp_get_dpcd only when error" has been added to the 4.4-stable tree

Patch "drm/amdgpu: return from atombios_dp_get_dpcd only when error" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/amdgpu: return from atombios_dp_get_dpcd only when error

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-amdgpu-return-from-atombios_dp_get_dpcd-only-when-error.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@vger.kernel.org> know about it.


>From 0b39c531cfa12dad54eac238c2e303b994df1ef7 Mon Sep 17 00:00:00 2001
From: Arindam Nath <arindam.nath@amd.com>
Date: Wed, 2 Mar 2016 17:19:01 +0530
Subject: drm/amdgpu: return from atombios_dp_get_dpcd only when error

From: Arindam Nath <arindam.nath@amd.com>

commit 0b39c531cfa12dad54eac238c2e303b994df1ef7 upstream.

In amdgpu_connector_hotplug(), we need to start DP link
training only after we have received DPCD. The function
amdgpu_atombios_dp_get_dpcd() returns non-zero value only
when an error condition is met, otherwise returns zero.
So in case the function encounters an error, we need to
skip rest of the code and return from amdgpu_connector_hotplug()
immediately. Only when we are successfull in reading DPCD
pin, we should carry on with turning-on the monitor.

Signed-off-by: Arindam Nath <arindam.nath@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -77,7 +77,7 @@ void amdgpu_connector_hotplug(struct drm
 			} 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))
+				if (amdgpu_atombios_dp_get_dpcd(amdgpu_connector))
 					return;
 
 				/* set it to OFF so that drm_helper_connector_dpms()


Patches currently in stable-queue which might be from arindam.nath@amd.com are

queue-4.4/drm-amdgpu-return-from-atombios_dp_get_dpcd-only-when-error.patch