The Lenovo Legion 5 15ARH05 (Renoir) ships a BOE 0x08DF eDP panel that advertises AUX/DPCD backlight control, so amdgpu's automatic detection (amdgpu_backlight == -1) selects AUX. On this panel the AUX backlight path has no effect: brightness writes are accepted but the panel level never changes, the display is stuck at a fixed brightness and max_brightness is reported as a bogus 511000. As a result neither the desktop brightness slider nor the brightness hotkeys do anything.
Forcing PWM backlight (amdgpu.backlight=0) restores working control: max_brightness becomes 65535 and the level tracks writes. This has long been applied by users as a manual kernel-parameter workaround. Extend the generic panel backlight quirk with a force_pwm flag, add an entry for the Legion 5 15ARH05 / BOE 0x08DF panel, and have amdgpu disable AUX backlight (use PWM) when the quirk matches and the user lets the driver auto-select the backlight type. Signed-off-by: Alessandro Rinaldi <[email protected]> Tested-by: Alessandro Rinaldi <[email protected]> --- This overlaps with the "force backlight type" patches for TUXEDO devices (amd and i915). If a single shared mechanism for forcing PWM is preferred, I'm happy to respin on top of it. .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_backlight.c | 7 +++++-- drivers/gpu/drm/drm_panel_backlight_quirks.c | 9 +++++++++ include/drm/drm_utils.h | 1 + 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_backlight.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_backlight.c index f19092a32..9ae1c1b0f 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_backlight.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_backlight.c @@ -486,6 +486,8 @@ void amdgpu_dm_update_connector_ext_caps(struct amdgpu_dm_connector *aconnector) caps->ext_caps = &aconnector->dc_link->dpcd_sink_ext_caps; caps->aux_support = false; + panel_backlight_quirk = drm_get_panel_backlight_quirk(aconnector->drm_edid); + if (caps->ext_caps->bits.oled == 1 /* * || @@ -498,6 +500,9 @@ void amdgpu_dm_update_connector_ext_caps(struct amdgpu_dm_connector *aconnector) caps->aux_support = false; else if (amdgpu_backlight == 1) caps->aux_support = true; + else if (!IS_ERR_OR_NULL(panel_backlight_quirk) && + panel_backlight_quirk->force_pwm) + caps->aux_support = false; if (caps->aux_support) aconnector->dc_link->backlight_control_type = BACKLIGHT_CONTROL_AMD_AUX; @@ -513,8 +518,6 @@ void amdgpu_dm_update_connector_ext_caps(struct amdgpu_dm_connector *aconnector) else caps->aux_min_input_signal = 1; - panel_backlight_quirk = - drm_get_panel_backlight_quirk(aconnector->drm_edid); if (!IS_ERR_OR_NULL(panel_backlight_quirk)) { if (panel_backlight_quirk->min_brightness) { caps->min_input_signal = diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/drm/drm_panel_backlight_quirks.c index 537dc6dd0..2d0238382 100644 --- a/drivers/gpu/drm/drm_panel_backlight_quirks.c +++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c @@ -21,6 +21,15 @@ struct drm_get_panel_backlight_quirk { }; static const struct drm_get_panel_backlight_quirk drm_panel_min_backlight_quirks[] = { + /* Lenovo Legion 5 15ARH05, AUX backlight non-functional, force PWM */ + { + .dmi_match.field = DMI_SYS_VENDOR, + .dmi_match.value = "LENOVO", + .dmi_match_other.field = DMI_PRODUCT_VERSION, + .dmi_match_other.value = "Lenovo Legion 5 15ARH05", + .ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E', 0x08df), + .quirk = { .force_pwm = true, }, + }, /* 13 inch matte panel */ { .dmi_match.field = DMI_BOARD_VENDOR, diff --git a/include/drm/drm_utils.h b/include/drm/drm_utils.h index 6a46f755d..7e077484c 100644 --- a/include/drm/drm_utils.h +++ b/include/drm/drm_utils.h @@ -19,6 +19,7 @@ int drm_get_panel_orientation_quirk(int width, int height); struct drm_panel_backlight_quirk { u16 min_brightness; u32 brightness_mask; + bool force_pwm; }; const struct drm_panel_backlight_quirk * -- 2.53.0
