This is a note to let you know that I've just added the patch titled
drm/amd/display: Add a backlight module option
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-add-a-backlight-module-option.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7a46f05e5e163c00e41892e671294286e53fe15c Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@xxxxxxx>
Date: Wed, 3 Feb 2021 13:42:41 +0100
Subject: drm/amd/display: Add a backlight module option
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)
Patches currently in stable-queue which might be from tiwai@xxxxxxx are
queue-5.10/drm-amd-display-add-a-backlight-module-option.patch
