On 2018-11-20 10:16 a.m., David Francis wrote:
> ACPI ATIF has a function called query
> backlight transfer characteristics. Among the
> information returned by this function is
> the minimum and maximum input signals for the
> backlight
>
> Call that function on ACPI init. When DM
> backlight device is updated, copy over the
> backlight caps into DM, but only once. Use
> the backlight caps in the backlight-to-dc
> calculation.
>
> Signed-off-by: David Francis <David.Francis@xxxxxxx>
Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx>
Harry
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 3 +
> drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 83 +++++++++++++++++++
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 59 ++++++++++---
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 13 +++
> drivers/gpu/drm/amd/include/amd_acpi.h | 24 ++++++
> 5 files changed, 170 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 2c80453ca350..adbad0e2d4ea 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1255,6 +1255,9 @@ bool amdgpu_acpi_is_pcie_performance_request_supported(struct amdgpu_device *ade
> int amdgpu_acpi_pcie_performance_request(struct amdgpu_device *adev,
> u8 perf_req, bool advertise);
> int amdgpu_acpi_pcie_notify_device_ready(struct amdgpu_device *adev);
> +
> +void amdgpu_acpi_get_backlight_caps(struct amdgpu_device *adev,
> + struct amdgpu_dm_backlight_caps *caps);
> #else
> static inline int amdgpu_acpi_init(struct amdgpu_device *adev) { return 0; }
> static inline void amdgpu_acpi_fini(struct amdgpu_device *adev) { }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> index 471266901d1b..47db65926d71 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> @@ -65,6 +65,7 @@ struct amdgpu_atif {
> struct amdgpu_atif_functions functions;
> struct amdgpu_atif_notification_cfg notification_cfg;
> struct amdgpu_encoder *encoder_for_bl;
> + struct amdgpu_dm_backlight_caps backlight_caps;
> };
>
> /* Call the ATIF method
> @@ -297,6 +298,65 @@ static int amdgpu_atif_get_notification_params(struct amdgpu_atif *atif)
> return err;
> }
>
> +/**
> + * amdgpu_atif_query_backlight_caps - get min and max backlight input signal
> + *
> + * @handle: acpi handle
> + *
> + * Execute the QUERY_BRIGHTNESS_TRANSFER_CHARACTERISTICS ATIF function
> + * to determine the acceptable range of backlight values
> + *
> + * Backlight_caps.caps_valid will be set to true if the query is successful
> + *
> + * The input signals are in range 0-255
> + *
> + * This function assumes the display with backlight is the first LCD
> + *
> + * Returns 0 on success, error on failure.
> + */
> +static int amdgpu_atif_query_backlight_caps(struct amdgpu_atif *atif)
> +{
> + union acpi_object *info;
> + struct atif_qbtc_output characteristics;
> + struct atif_qbtc_arguments arguments;
> + struct acpi_buffer params;
> + size_t size;
> + int err = 0;
> +
> + arguments.size = sizeof(arguments);
> + arguments.requested_display = ATIF_QBTC_REQUEST_LCD1;
> +
> + params.length = sizeof(arguments);
> + params.pointer = (void *)&arguments;
> +
> + info = amdgpu_atif_call(atif,
> + ATIF_FUNCTION_QUERY_BRIGHTNESS_TRANSFER_CHARACTERISTICS,
> + ¶ms);
> + if (!info) {
> + err = -EIO;
> + goto out;
> + }
> +
> + size = *(u16 *) info->buffer.pointer;
> + if (size < 10) {
> + err = -EINVAL;
> + goto out;
> + }
> +
> + memset(&characteristics, 0, sizeof(characteristics));
> + size = min(sizeof(characteristics), size);
> + memcpy(&characteristics, info->buffer.pointer, size);
> +
> + atif->backlight_caps.caps_valid = true;
> + atif->backlight_caps.min_input_signal =
> + characteristics.min_input_signal;
> + atif->backlight_caps.max_input_signal =
> + characteristics.max_input_signal;
> +out:
> + kfree(info);
> + return err;
> +}
> +
> /**
> * amdgpu_atif_get_sbios_requests - get requested sbios event
> *
> @@ -786,6 +846,17 @@ int amdgpu_acpi_init(struct amdgpu_device *adev)
> }
> }
>
> + if (atif->functions.query_backlight_transfer_characteristics) {
> + ret = amdgpu_atif_query_backlight_caps(atif);
> + if (ret) {
> + DRM_DEBUG_DRIVER("Call to QUERY_BACKLIGHT_TRANSFER_CHARACTERISTICS failed: %d\n",
> + ret);
> + atif->backlight_caps.caps_valid = false;
> + }
> + } else {
> + atif->backlight_caps.caps_valid = false;
> + }
> +
> out:
> adev->acpi_nb.notifier_call = amdgpu_acpi_event;
> register_acpi_notifier(&adev->acpi_nb);
> @@ -793,6 +864,18 @@ int amdgpu_acpi_init(struct amdgpu_device *adev)
> return ret;
> }
>
> +void amdgpu_acpi_get_backlight_caps(struct amdgpu_device *adev,
> + struct amdgpu_dm_backlight_caps *caps)
> +{
> + if (!adev->atif) {
> + caps->caps_valid = false;
> + return;
> + }
> + caps->caps_valid = adev->atif->backlight_caps.caps_valid;
> + caps->min_input_signal = adev->atif->backlight_caps.min_input_signal;
> + caps->max_input_signal = adev->atif->backlight_caps.max_input_signal;
> +}
> +
> /**
> * amdgpu_acpi_fini - tear down driver acpi support
> *
> 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 090a602f3014..0bccea073f9d 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1590,27 +1590,60 @@ static int amdgpu_dm_mode_config_init(struct amdgpu_device *adev)
> return 0;
> }
>
> +#define AMDGPU_DM_DEFAULT_MIN_BACKLIGHT 12
> +#define AMDGPU_DM_DEFAULT_MAX_BACKLIGHT 255
> +
> #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) ||\
> defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
>
> +static void amdgpu_dm_update_backlight_caps(struct amdgpu_display_manager *dm)
> +{
> +#if defined(CONFIG_ACPI)
> + struct amdgpu_dm_backlight_caps caps;
> +
> + if (dm->backlight_caps.caps_valid)
> + return;
> +
> + amdgpu_acpi_get_backlight_caps(dm->adev, &caps);
> + if (caps.caps_valid) {
> + dm->backlight_caps.min_input_signal = caps.min_input_signal;
> + dm->backlight_caps.max_input_signal = caps.max_input_signal;
> + dm->backlight_caps.caps_valid = true;
> + } else {
> + dm->backlight_caps.min_input_signal =
> + AMDGPU_DM_DEFAULT_MIN_BACKLIGHT;
> + dm->backlight_caps.max_input_signal =
> + AMDGPU_DM_DEFAULT_MAX_BACKLIGHT;
> + }
> +#else
> + dm->backlight_min_input_signal = AMDGPU_DM_DEFAULT_MIN_BACKLIGHT;
> + dm->backlight_max_input_signal = AMDGPU_DM_DEFAULT_MAX_BACKLIGHT;
> +#endif
> +}
> +
> static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
> {
> struct amdgpu_display_manager *dm = bl_get_data(bd);
> + struct amdgpu_dm_backlight_caps caps;
> + uint32_t brightness = bd->props.brightness;
>
> - /* backlight_pwm_u16_16 parameter is in unsigned 32 bit, 16 bit integer
> - * and 16 bit fractional, where 1.0 is max backlight value.
> - * bd->props.brightness is 8 bit format and needs to be converted by
> - * scaling via copy lower byte to upper byte of 16 bit value.
> - */
> - uint32_t brightness = bd->props.brightness * 0x101;
> -
> + amdgpu_dm_update_backlight_caps(dm);
> + caps = dm->backlight_caps;
> /*
> - * PWM interperts 0 as 100% rather than 0% because of HW
> - * limitation for level 0. So limiting minimum brightness level
> - * to 1.
> + * The brightness input is in the range 0-255
> + * It needs to be rescaled to be between the
> + * requested min and max input signal
> + *
> + * It also needs to be scaled up by 0x101 to
> + * match the DC interface which has a range of
> + * 0 to 0xffff
> */
> - if (bd->props.brightness < 1)
> - brightness = 0x101;
> + brightness =
> + brightness
> + * 0x101
> + * (caps.max_input_signal - caps.min_input_signal)
> + / AMDGPU_MAX_BL_LEVEL
> + + caps.min_input_signal * 0x101;
>
> if (dc_link_set_backlight_level(dm->backlight_link,
> brightness, 0, 0))
> @@ -1640,6 +1673,8 @@ amdgpu_dm_register_backlight_device(struct amdgpu_display_manager *dm)
> char bl_name[16];
> struct backlight_properties props = { 0 };
>
> + amdgpu_dm_update_backlight_caps(dm);
> +
> props.max_brightness = AMDGPU_MAX_BL_LEVEL;
> props.brightness = AMDGPU_MAX_BL_LEVEL;
> props.type = BACKLIGHT_RAW;
> 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 3c2fbfac938f..b8e724a5fd6d 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> @@ -83,6 +83,18 @@ struct dm_comressor_info {
> uint64_t gpu_addr;
> };
>
> +/**
> + * struct amdgpu_dm_backlight_caps - Usable range of backlight values from ACPI
> + * @min_input_signal: minimum possible input in range 0-255
> + * @max_input_signal: maximum possible input in range 0-255
> + * @caps_valid: true if these values are from the ACPI interface
> + */
> +struct amdgpu_dm_backlight_caps {
> + int min_input_signal;
> + int max_input_signal;
> + bool caps_valid;
> +};
> +
> /**
> * struct amdgpu_display_manager - Central amdgpu display manager device
> *
> @@ -158,6 +170,7 @@ struct amdgpu_display_manager {
> struct backlight_device *backlight_dev;
>
> const struct dc_link *backlight_link;
> + struct amdgpu_dm_backlight_caps backlight_caps;
>
> struct mod_freesync *freesync_module;
>
> diff --git a/drivers/gpu/drm/amd/include/amd_acpi.h b/drivers/gpu/drm/amd/include/amd_acpi.h
> index 8980edfe5fa9..c72cbfe8f684 100644
> --- a/drivers/gpu/drm/amd/include/amd_acpi.h
> +++ b/drivers/gpu/drm/amd/include/amd_acpi.h
> @@ -52,6 +52,30 @@ struct atif_sbios_requests {
> u8 backlight_level; /* panel backlight level (0-255) */
> } __packed;
>
> +struct atif_qbtc_arguments {
> + u16 size; /* structure size in bytes (includes size field) */
> + u8 requested_display; /* which display is requested */
> +} __packed;
> +
> +#define ATIF_QBTC_MAX_DATA_POINTS 99
> +
> +struct atif_qbtc_data_point {
> + u8 luminance; /* luminance in percent */
> + u8 ipnut_signal; /* input signal in range 0-255 */
> +} __packed;
> +
> +struct atif_qbtc_output {
> + u16 size; /* structure size in bytes (includes size field) */
> + u16 flags; /* all zeroes */
> + u8 error_code; /* error code */
> + u8 ac_level; /* default brightness on AC power */
> + u8 dc_level; /* default brightness on DC power */
> + u8 min_input_signal; /* max input signal in range 0-255 */
> + u8 max_input_signal; /* min input signal in range 0-255 */
> + u8 number_of_points; /* number of data points */
> + struct atif_qbtc_data_point data_points[ATIF_QBTC_MAX_DATA_POINTS];
> +} __packed;
> +
> #define ATIF_NOTIFY_MASK 0x3
> #define ATIF_NOTIFY_NONE 0
> #define ATIF_NOTIFY_81 1
>
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