[PATCH] drm/amd: Only allow one entity to control ABM
Christian König
ckoenig.leichtzumerken at gmail.com
Fri Feb 16 14:38:57 UTC 2024
Am 16.02.24 um 15:07 schrieb Mario Limonciello:
> By exporting ABM to sysfs it's possible that DRM master and software
> controlling the sysfs file fight over the value programmed for ABM.
>
> Adjust the module parameter behavior to control who control ABM:
> -2: DRM
> -1: sysfs (IE via software like power-profiles-daemon)
Well that sounds extremely awkward. Why should a power-profiles-deamon
has control over the panel power saving features?
I mean we are talking about things like reducing backlight level when
the is inactivity, don't we?
Regards,
Christian.
> 0-4: User via command line
>
> Also introduce a Kconfig option that allows distributions to choose
> the default policy that is appropriate for them.
>
> Fixes: f97e4303da16 ("drm/amd/display: add panel_power_savings sysfs entry to eDP connectors")
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
> ---
> Cc: Hamza Mahfooz <Hamza.Mahfooz at amd.com>
> Cc: Harry Wentland <Harry.Wentland at amd.com>
> Cc: Sun peng (Leo) Li <Sunpeng.Li at amd.com>
> drivers/gpu/drm/amd/amdgpu/Kconfig | 72 +++++++++++++++++++
> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 23 +++---
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 +-
> 3 files changed, 90 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/Kconfig b/drivers/gpu/drm/amd/amdgpu/Kconfig
> index 22d88f8ef527..2ab57ccf6f21 100644
> --- a/drivers/gpu/drm/amd/amdgpu/Kconfig
> +++ b/drivers/gpu/drm/amd/amdgpu/Kconfig
> @@ -80,6 +80,78 @@ config DRM_AMDGPU_WERROR
> Add -Werror to the build flags for amdgpu.ko.
> Only enable this if you are warning code for amdgpu.ko.
>
> +choice
> + prompt "Amdgpu panel power Savings"
> + default AMDGPU_SYSFS_ABM
> + help
> + Control the default behavior for adaptive panel power savings.
> +
> + Panel power savings features will sacrifice color accuracy
> + in exchange for power savings.
> +
> + This can be configured for:
> + - dynamic control by the DRM master
> + - dynamic control by sysfs nodes
> + - statically by the user at kernel compile time
> +
> + This value can also be overridden by the amdgpu.abmlevel
> + module parameter.
> +
> +config AMDGPU_DRM_ABM
> + bool "DRM Master control"
> + help
> + Export a property called 'abm_level' that can be
> + manipulated by the DRM master for supported hardware.
> +
> +config AMDGPU_SYSFS_ABM
> + bool "sysfs control"
> + help
> + Export a sysfs file 'panel_power_savings' that can be
> + manipulated by userspace for supported hardware.
> +
> +config AMDGPU_HARDCODE_ABM0
> + bool "No Panel power savings"
> + help
> + Disable panel power savings.
> + It can only overridden by the kernel command line.
> +
> +config AMDGPU_HARDCODE_ABM1
> + bool "25% Panel power savings"
> + help
> + Set the ABM panel power savings algorithm to 25%.
> + It can only overridden by the kernel command line.
> +
> +config AMDGPU_HARDCODE_ABM2
> + bool "50% Panel power savings"
> + help
> + Set the ABM panel power savings algorithm to 50%.
> + It can only overridden by the kernel command line.
> +
> +config AMDGPU_HARDCODE_ABM3
> + bool "75% Panel power savings"
> + help
> + Set the ABM panel power savings algorithm to 75%.
> + It can only overridden by the kernel command line.
> +
> +config AMDGPU_HARDCODE_ABM4
> + bool "100% Panel power savings"
> + help
> + Set the ABM panel power savings algorithm to 100%.
> + It can only overridden by the kernel command line.
> +endchoice
> +
> +config AMDGPU_ABM_POLICY
> + int
> + default -2 if AMDGPU_DRM_ABM
> + default -1 if AMDGPU_SYSFS_ABM
> + default 0 if AMDGPU_HARDCODE_ABM0
> + default 1 if AMDGPU_HARDCODE_ABM1
> + default 2 if AMDGPU_HARDCODE_ABM2
> + default 3 if AMDGPU_HARDCODE_ABM3
> + default 4 if AMDGPU_HARDCODE_ABM4
> + default -1
> +
> +
> source "drivers/gpu/drm/amd/acp/Kconfig"
> source "drivers/gpu/drm/amd/display/Kconfig"
> source "drivers/gpu/drm/amd/amdkfd/Kconfig"
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index af7fae7907d7..00d6c8b58716 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -844,17 +844,24 @@ module_param_named(visualconfirm, amdgpu_dc_visual_confirm, uint, 0444);
> * DOC: abmlevel (uint)
> * Override the default ABM (Adaptive Backlight Management) level used for DC
> * enabled hardware. Requires DMCU to be supported and loaded.
> - * Valid levels are 0-4. A value of 0 indicates that ABM should be disabled by
> - * default. Values 1-4 control the maximum allowable brightness reduction via
> - * the ABM algorithm, with 1 being the least reduction and 4 being the most
> - * reduction.
> + * Valid levels are -2 through 4.
> *
> - * Defaults to -1, or disabled. Userspace can only override this level after
> - * boot if it's set to auto.
> + * -2: indicates that ABM should be controlled by DRM property 'abm_level.
> + * -1: indicates that ABM should be controlled by the sysfs file
> + * 'panel_power_savings'.
> + * 0: indicates that ABM should be disabled.
> + * 1-4: control the maximum allowable brightness reduction via
> + * the ABM algorithm, with 1 being the least reduction and 4 being the most
> + * reduction.
> + *
> + * Both the DRM property 'abm_level' and the sysfs file 'panel_power_savings'
> + * will only be available on supported hardware configurations.
> + *
> + * The default value is configured by kernel configuration option AMDGPU_ABM_POLICY
> */
> -int amdgpu_dm_abm_level = -1;
> +int amdgpu_dm_abm_level = CONFIG_AMDGPU_ABM_POLICY;
> MODULE_PARM_DESC(abmlevel,
> - "ABM level (0 = off, 1-4 = backlight reduction level, -1 auto (default))");
> + "ABM level (0 = off, 1-4 = backlight reduction level, -1 = sysfs control, -2 = drm control");
> module_param_named(abmlevel, amdgpu_dm_abm_level, int, 0444);
>
> int amdgpu_backlight = -1;
> 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 b9ac3d2f8029..147fe744f82e 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -6515,7 +6515,7 @@ static void amdgpu_dm_connector_unregister(struct drm_connector *connector)
> struct amdgpu_dm_connector *amdgpu_dm_connector = to_amdgpu_dm_connector(connector);
>
> if (connector->connector_type == DRM_MODE_CONNECTOR_eDP &&
> - amdgpu_dm_abm_level < 0)
> + amdgpu_dm_abm_level == -1)
> sysfs_remove_group(&connector->kdev->kobj, &amdgpu_group);
>
> drm_dp_aux_unregister(&amdgpu_dm_connector->dm_dp_aux.aux);
> @@ -6623,7 +6623,7 @@ amdgpu_dm_connector_late_register(struct drm_connector *connector)
> int r;
>
> if (connector->connector_type == DRM_MODE_CONNECTOR_eDP &&
> - amdgpu_dm_abm_level < 0) {
> + amdgpu_dm_abm_level == -1) {
> r = sysfs_create_group(&connector->kdev->kobj,
> &amdgpu_group);
> if (r)
> @@ -7654,7 +7654,7 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
>
> if (connector_type == DRM_MODE_CONNECTOR_eDP &&
> (dc_is_dmcu_initialized(adev->dm.dc) ||
> - adev->dm.dc->ctx->dmub_srv) && amdgpu_dm_abm_level < 0) {
> + adev->dm.dc->ctx->dmub_srv) && amdgpu_dm_abm_level == -2) {
> drm_object_attach_property(&aconnector->base.base,
> adev->mode_info.abm_level_property, 0);
> }
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