From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> From: Takashi Iwai <tiwai@xxxxxxx> commit 7a46f05e5e163c00e41892e671294286e53fe15c upstream. There seem devices that don't work with the aux channel backlight control. For allowing such users to test with the other backlight control method, provide a new module option, aux_backlight, to specify enabling or disabling the aux backport support explicitly. As default, the aux support is detected by the hardware capability. v2: make the backlight option generic in case we add future backlight types (Alex) BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1180749 BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1438 Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 + drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 4 ++++ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 +++++ 3 files changed, 10 insertions(+) --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h @@ -178,6 +178,7 @@ extern uint amdgpu_smu_memory_pool_size; extern uint amdgpu_dc_feature_mask; extern uint amdgpu_dc_debug_mask; extern uint amdgpu_dm_abm_level; +extern int amdgpu_backlight; extern struct amdgpu_mgpu_info mgpu_info; extern int amdgpu_ras_enable; extern uint amdgpu_ras_mask; --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c @@ -768,6 +768,10 @@ uint amdgpu_dm_abm_level = 0; MODULE_PARM_DESC(abmlevel, "ABM level (0 = off (default), 1-4 = backlight reduction level) "); module_param_named(abmlevel, amdgpu_dm_abm_level, uint, 0444); +int amdgpu_backlight = -1; +MODULE_PARM_DESC(backlight, "Backlight control (0 = pwm, 1 = aux, -1 auto (default))"); +module_param_named(backlight, amdgpu_backlight, bint, 0444); + /** * DOC: tmz (int) * Trusted Memory Zone (TMZ) is a method to protect data being written --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -2140,6 +2140,11 @@ static void update_connector_ext_caps(st caps->ext_caps->bits.hdr_aux_backlight_control == 1) caps->aux_support = true; + if (amdgpu_backlight == 0) + caps->aux_support = false; + else if (amdgpu_backlight == 1) + caps->aux_support = true; + /* From the specification (CTA-861-G), for calculating the maximum * luminance we need to use: * Luminance = 50*2**(CV/32)
