[PATCH] drm/amd/display: Set default brightness according to ACPI

[Leo Li]

On 2024-06-07 09:49, Alex Deucher wrote:
> On Fri, Jun 7, 2024 at 3:22 AM Mario Limonciello
> <mario.limonciello at amd.com> wrote:
>>
>> Currently, amdgpu will always set up the brightness at 100% when it
>> loads.  However this is jarring when the BIOS has it previously
>> programmed to a much lower value.
>>
>> The ACPI ATIF method includes two members for "ac_level" and "dc_level".
>> These represent the default values that should be used if the system is
>> brought up in AC and DC respectively.
>>
>> Use these values to set up the default brightness when the backlight
>> device is registered.
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
> 
> Acked-by: Alex Deucher <alexander.deucher at amd.com>

Reviewed-by: Leo Li <sunpeng.li at amd.com>

> 
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c          |  4 ++++
>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++++++-
>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  8 ++++++++
>>   3 files changed, 23 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
>> index 7099ff9cf8c5..f85ace0384d2 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
>> @@ -383,6 +383,8 @@ static int amdgpu_atif_query_backlight_caps(struct amdgpu_atif *atif)
>>                          characteristics.min_input_signal;
>>          atif->backlight_caps.max_input_signal =
>>                          characteristics.max_input_signal;
>> +       atif->backlight_caps.ac_level = characteristics.ac_level;
>> +       atif->backlight_caps.dc_level = characteristics.dc_level;
>>   out:
>>          kfree(info);
>>          return err;
>> @@ -1268,6 +1270,8 @@ void amdgpu_acpi_get_backlight_caps(struct amdgpu_dm_backlight_caps *caps)
>>          caps->caps_valid = atif->backlight_caps.caps_valid;
>>          caps->min_input_signal = atif->backlight_caps.min_input_signal;
>>          caps->max_input_signal = atif->backlight_caps.max_input_signal;
>> +       caps->ac_level = atif->backlight_caps.ac_level;
>> +       caps->dc_level = atif->backlight_caps.dc_level;
>>   }
>>
>>   /**
>> 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 5fd7210b2479..71aa0c518951 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -77,6 +77,7 @@
>>   #include <linux/types.h>
>>   #include <linux/pm_runtime.h>
>>   #include <linux/pci.h>
>> +#include <linux/power_supply.h>
>>   #include <linux/firmware.h>
>>   #include <linux/component.h>
>>   #include <linux/dmi.h>
>> @@ -4321,6 +4322,7 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector)
>>          struct drm_device *drm = aconnector->base.dev;
>>          struct amdgpu_display_manager *dm = &drm_to_adev(drm)->dm;
>>          struct backlight_properties props = { 0 };
>> +       struct amdgpu_dm_backlight_caps caps = { 0 };
>>          char bl_name[16];
>>
>>          if (aconnector->bl_idx == -1)
>> @@ -4333,8 +4335,16 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector)
>>                  return;
>>          }
>>
>> +       amdgpu_acpi_get_backlight_caps(&caps);
>> +       if (caps.caps_valid) {
>> +               if (power_supply_is_system_supplied() > 0)
>> +                       props.brightness = caps.ac_level;
>> +               else
>> +                       props.brightness = caps.dc_level;
>> +       } else
>> +               props.brightness = AMDGPU_MAX_BL_LEVEL;
>> +
>>          props.max_brightness = AMDGPU_MAX_BL_LEVEL;
>> -       props.brightness = AMDGPU_MAX_BL_LEVEL;
>>          props.type = BACKLIGHT_RAW;
>>
>>          snprintf(bl_name, sizeof(bl_name), "amdgpu_bl%d",
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
>> index b246e82f5b0d..df72cb71e95a 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
>> @@ -173,6 +173,14 @@ struct amdgpu_dm_backlight_caps {
>>           * @aux_support: Describes if the display supports AUX backlight.
>>           */
>>          bool aux_support;
>> +       /**
>> +        * @ac_level: the default brightness if booted on AC
>> +        */
>> +       u8 ac_level;
>> +       /**
>> +        * @dc_level: the default brightness if booted on DC
>> +        */
>> +       u8 dc_level;
>>   };
>>
>>   /**
>> --
>> 2.43.0
>>