drm/amd/display: Add a backlight module option

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@amd.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Takashi Iwai 2021-02-03 13:42:41 +01:00 committed by Greg Kroah-Hartman
parent e30ce84181
commit 55086176c7
3 changed files with 10 additions and 0 deletions

View File

@ -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;

View File

@ -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

View File

@ -2140,6 +2140,11 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
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)