FAILED: Patch "drm/amd/display: Drop 'acrtc' and add 'new_crtc_state' NULL check for writeback requests." failed to apply to 4.19-stable tree

[Sasha Levin]

The patch below does not apply to the 4.19-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 at vger.kernel.org>.

Thanks,
Sasha

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

>From b2f26f49e84bea03dddb5f37ff137c97b165107b Mon Sep 17 00:00:00 2001
From: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
Date: Sat, 13 Jan 2024 14:32:27 +0530
Subject: [PATCH] drm/amd/display: Drop 'acrtc' and add 'new_crtc_state' NULL
 check for writeback requests.

Return value of 'to_amdgpu_crtc' which is container_of(...) can't be
null, so it's null check 'acrtc' is dropped.

Fixing the below:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9302 amdgpu_dm_atomic_commit_tail() error: we previously assumed 'acrtc' could be null (see line 9299)

Added 'new_crtc_state' NULL check for function
'drm_atomic_get_new_crtc_state' that retrieves the new state for a CRTC,
while enabling writeback requests.

Cc: stable at vger.kernel.org
Cc: Alex Hung <alex.hung at amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai at amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz at amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
Reviewed-by: Alex Hung <alex.hung at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

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 36af104e7663c..8623722e954f9 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -9327,10 +9327,10 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 		if (!new_con_state->writeback_job)
 			continue;
 
-		new_crtc_state = NULL;
+		new_crtc_state = drm_atomic_get_new_crtc_state(state, &acrtc->base);
 
-		if (acrtc)
-			new_crtc_state = drm_atomic_get_new_crtc_state(state, &acrtc->base);
+		if (!new_crtc_state)
+			continue;
 
 		if (acrtc->wb_enabled)
 			continue;
-- 
2.43.0