From 5e19e2b57b6bb640d68dfc7991e1e182922cf867 Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello@amd.com>
Date: Sun, 23 Feb 2025 00:04:35 -0600
Subject: [PATCH] drm/amd/display: Restore correct backlight brightness after a
GPU reset
[Why]
GPU reset will attempt to restore cached state, but brightness doesn't
get restored. It will come back at 100% brightness, but userspace thinks
it's the previous value.
[How]
When running resume sequence if GPU is in reset restore brightness
to previous value.
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 ++++++++++
1 file changed, 10 insertions(+)
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 5ae521d1b74be..bf69cd50712e3 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -250,6 +250,10 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
static void handle_hpd_irq_helper(struct amdgpu_dm_connector *aconnector);
static void handle_hpd_rx_irq(void *param);
+static void amdgpu_dm_backlight_set_level(struct amdgpu_display_manager *dm,
+ int bl_idx,
+ u32 user_brightness);
+
static bool
is_timing_unchanged_for_freesync(struct drm_crtc_state *old_crtc_state,
struct drm_crtc_state *new_crtc_state);
@@ -3432,6 +3436,12 @@ static int dm_resume(struct amdgpu_ip_block *ip_block)
mutex_unlock(&dm->dc_lock);
+ /* set the backlight after a reset */
+ for (i = 0; i < dm->num_of_edps; i++) {
+ if (dm->backlight_dev[i])
+ amdgpu_dm_backlight_set_level(dm, i, dm->brightness[i]);
+ }
+
return 0;
}
--
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