FAILED: patch "[PATCH] drm/amd/display: Fix OLED brightness control on eDP" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-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 dab60582685aabdae2d4ff7ce716456bd0dc7a0f Mon Sep 17 00:00:00 2001
From: Roman Li <Roman.Li@amd.com>
Date: Wed, 17 Nov 2021 10:05:36 -0500
Subject: [PATCH] drm/amd/display: Fix OLED brightness control on eDP
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

[Why]
After commit ("drm/amdgpu/display: add support for multiple backlights")
number of eDPs is defined while registering backlight device.
However the panel's extended caps get updated once before register call.
That leads to regression with extended caps like oled brightness control.

[How]
Update connector ext caps after register_backlight_device

Fixes: 7fd13baeb7a3a4 ("drm/amdgpu/display: add support for multiple backlights")
Link: https://www.reddit.com/r/AMDLaptops/comments/qst0fm/after_updating_to_linux_515_my_brightness/

Signed-off-by: Roman Li <Roman.Li@amd.com>
Tested-by: Samuel Čavoj <samuel@cavoj.net>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jasdeep Dhillon <Jasdeep.Dhillon@amd.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 c911b30de658..c27cb47bc988 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4242,7 +4242,8 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 		} else if (dc_link_detect(link, DETECT_REASON_BOOT)) {
 			amdgpu_dm_update_connector_after_detect(aconnector);
 			register_backlight_device(dm, link);
-
+			if (dm->num_of_edps)
+				update_connector_ext_caps(aconnector);
 			if (psr_feature_enabled)
 				amdgpu_dm_set_psr_caps(link);
 		}