6.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matthew Schwartz matthew.schwartz@linux.dev
commit 44b0fed0a5947f54fd14255cd0766df952267bc5 upstream.
On clients that utilize AMD_PRIVATE_COLOR properties for HDR support, brightness sliders can include a hardware controlled portion and a gamma-based portion. This is the case on the Steam Deck OLED when using gamescope with Steam as a client.
When a user sets a brightness level while HDR is active, the gamma-based portion and/or hardware portion are adjusted to achieve the desired brightness. However, when a modeset takes place while the gamma-based portion is in-use, restoring the hardware brightness level overrides the user's overall brightness level and results in a mismatch between what the slider reports and the display's current brightness.
To avoid overriding gamma-based brightness, only restore HW backlight level after boot or resume. This ensures that the backlight level is set correctly after the DC layer resets it while avoiding interference with subsequent modesets.
Fixes: 7875afafba84 ("drm/amd/display: Fix brightness level not retained over reboot") Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4551 Signed-off-by: Matthew Schwartz matthew.schwartz@linux.dev Reviewed-by: Mario Limonciello mario.limonciello@amd.com Signed-off-by: Mario Limonciello mario.limonciello@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com (cherry picked from commit a490c8d77d500b5981e739be3d59c60cfe382536) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 ++++++++---- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 7 +++++++ 2 files changed, 15 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -2035,6 +2035,8 @@ static int amdgpu_dm_init(struct amdgpu_
dc_hardware_init(adev->dm.dc);
+ adev->dm.restore_backlight = true; + adev->dm.hpd_rx_offload_wq = hpd_rx_irq_create_workqueue(adev); if (!adev->dm.hpd_rx_offload_wq) { drm_err(adev_to_drm(adev), "amdgpu: failed to create hpd rx offload workqueue.\n"); @@ -3396,6 +3398,7 @@ static int dm_resume(struct amdgpu_ip_bl dc_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D0);
dc_resume(dm->dc); + adev->dm.restore_backlight = true;
amdgpu_dm_irq_resume_early(adev);
@@ -9801,7 +9804,6 @@ static void amdgpu_dm_commit_streams(str 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) { @@ -9921,7 +9923,6 @@ static void amdgpu_dm_commit_streams(str 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", @@ -9978,13 +9979,16 @@ static void amdgpu_dm_commit_streams(str * 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 + * So we set the backlight level with dm->brightness value after initial + * set mode. Use restore_backlight flag to avoid setting backlight level + * for every subsequent mode set. */ - if (set_backlight_level) { + if (dm->restore_backlight) { for (i = 0; i < dm->num_of_edps; i++) { if (dm->backlight_dev[i]) amdgpu_dm_backlight_set_level(dm, i, dm->brightness[i]); } + dm->restore_backlight = false; } }
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h @@ -611,6 +611,13 @@ struct amdgpu_display_manager { u32 actual_brightness[AMDGPU_DM_MAX_NUM_EDP];
/** + * @restore_backlight: + * + * Flag to indicate whether to restore backlight after modeset. + */ + bool restore_backlight; + + /** * @aux_hpd_discon_quirk: * * quirk for hpd discon while aux is on-going.