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drm/amd/display: Add a backlight module option

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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
This commit is contained in:
Takashi Iwai 2021-02-03 13:42:41 +01:00 committed by Alex Deucher
parent 0ad3e64eb4
commit 7a46f05e5e
3 changed files with 10 additions and 0 deletions
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1
drivers/gpu/drm/amd/amdgpu/amdgpu.h
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@ -180,6 +180,7 @@ 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;

4
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
View File

@ -781,6 +781,10 @@ uint amdgpu_dm_abm_level;
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

5
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
View File

@ -2267,6 +2267,11 @@ 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)