FAILED: patch "[PATCH] drm/amd/display: add dmcub check on RENOIR" failed to apply to 5.7-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.7-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3b2e973dff59d88bee1d814ddf8762a24fc02b60 Mon Sep 17 00:00:00 2001
From: Aaron Ma <aaron.ma@canonical.com>
Date: Wed, 8 Jul 2020 04:16:22 -0400
Subject: [PATCH] drm/amd/display: add dmcub check on RENOIR

RENOIR loads dmub fw not dmcu, check dmcu only will prevent loading iram,
it breaks backlight control.

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=208277
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 10ac8076d4f2..db5e0bb0d935 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1358,7 +1358,7 @@ static int dm_late_init(void *handle)
 	struct dmcu *dmcu = NULL;
 	bool ret;
 
-	if (!adev->dm.fw_dmcu)
+	if (!adev->dm.fw_dmcu && !adev->dm.dmub_fw)
 		return detect_mst_link_for_all_connectors(adev->ddev);
 
 	dmcu = adev->dm.dc->res_pool->dmcu;