The patch below does not apply to the 6.6-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.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 4f26c95ffc21a91281429ed60180619bae19ae92 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024110902-backslid-snagged-6d02@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 4f26c95ffc21a91281429ed60180619bae19ae92 Mon Sep 17 00:00:00 2001 From: Tom Chung chiahsuan.chung@amd.com Date: Wed, 9 Oct 2024 17:09:38 +0800 Subject: [PATCH] drm/amd/display: Fix brightness level not retained over reboot

[Why] During boot up and resume the DC layer will reset the panel brightness to fix a flicker issue.

It will cause the dm->actual_brightness is not the current panel brightness level. (the dm->brightness is the correct panel level)

[How] Set the backlight level after do the set mode.

Cc: Mario Limonciello mario.limonciello@amd.com Cc: Alex Deucher alexander.deucher@amd.com Fixes: d9e865826c20 ("drm/amd/display: Simplify brightness initialization") Reported-by: Mark Herbert mark.herbert42@gmail.com Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3655 Reviewed-by: Sun peng Li sunpeng.li@amd.com Signed-off-by: Tom Chung chiahsuan.chung@amd.com Signed-off-by: Zaeem Mohamed zaeem.mohamed@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com (cherry picked from commit 7875afafba84817b791be6d2282b836695146060) 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 13421a58210d..07e9ce99694f 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -9429,6 +9429,7 @@ static void amdgpu_dm_commit_streams(struct drm_atomic_state *state, bool mode_set_reset_required = false; u32 i; struct dc_commit_streams_params params = {dc_state->streams, dc_state->stream_count}; + bool set_backlight_level = false;

/* Disable writeback */ for_each_old_connector_in_state(state, connector, old_con_state, i) { @@ -9548,6 +9549,7 @@ static void amdgpu_dm_commit_streams(struct drm_atomic_state *state, acrtc->hw_mode = new_crtc_state->mode; crtc->hwmode = new_crtc_state->mode; mode_set_reset_required = true; + set_backlight_level = true; } else if (modereset_required(new_crtc_state)) { drm_dbg_atomic(dev, "Atomic commit: RESET. crtc id %d:[%p]\n", @@ -9599,6 +9601,19 @@ static void amdgpu_dm_commit_streams(struct drm_atomic_state *state, acrtc->otg_inst = status->primary_otg_inst; } } + + /* During boot up and resume the DC layer will reset the panel brightness + * to fix a flicker issue. + * It will cause the dm->actual_brightness is not the current panel brightness + * level. (the dm->brightness is the correct panel level) + * So we set the backlight level with dm->brightness value after set mode + */ + if (set_backlight_level) { + for (i = 0; i < dm->num_of_edps; i++) { + if (dm->backlight_dev[i]) + amdgpu_dm_backlight_set_level(dm, i, dm->brightness[i]); + } + } }

static void dm_set_writeback(struct amdgpu_display_manager *dm,