From 00b493aca016eadbc9ba8f1d4e4f24adf7ee61dc Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 4 Mar 2021 12:41:03 -0500
Subject: [PATCH 4/4] drm/amd/display: Add a backlight module option
References: bsc#1180749
Patch-mainline: Submitted, amd-gfx ML
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
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
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(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index b6879d97c9c9..49267eb64302 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -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;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 4575192d9b08..b26e2fd1c538 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -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
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 0bc9a06b3f15..0523be612a48 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -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)
--
2.26.2