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@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@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@vger.kernel.org Cc: Alex Hung alex.hung@amd.com Cc: Aurabindo Pillai aurabindo.pillai@amd.com Cc: Rodrigo Siqueira Rodrigo.Siqueira@amd.com Cc: Hamza Mahfooz hamza.mahfooz@amd.com Signed-off-by: Srinivasan Shanmugam srinivasan.shanmugam@amd.com Reviewed-by: Alex Hung alex.hung@amd.com Signed-off-by: Alex Deucher alexander.deucher@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;