Commit 8dbd72cb authored by Mario Limonciello's avatar Mario Limonciello Committed by Alex Deucher
Browse files

drm/amd/display: Export full brightness range to userspace 



[WHY]
Userspace currently is offered a range from 0-0xFF but the PWM is
programmed from 0-0xFFFF.  This can be limiting to some software
that wants to apply greater granularity.

[HOW]
Convert internally to firmware values only when mapping custom
brightness curves because these are in 0-0xFF range. Advertise full
PWM range to userspace.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: default avatarRoman Li <roman.li@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarAlex Hung <alex.hung@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 148144f6

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

+27 −14
Original line number Diff line number Diff line
@@ -4721,9 +4721,23 @@ static int get_brightness_range(const struct amdgpu_dm_backlight_caps *caps, 
	return 1;

}



/* Rescale from [min..max] to [0..AMDGPU_MAX_BL_LEVEL] */

static inline u32 scale_input_to_fw(int min, int max, u64 input)

{

	return DIV_ROUND_CLOSEST_ULL(input * AMDGPU_MAX_BL_LEVEL, max - min);

}



/* Rescale from [0..AMDGPU_MAX_BL_LEVEL] to [min..max] */

static inline u32 scale_fw_to_input(int min, int max, u64 input)

{

	return min + DIV_ROUND_CLOSEST_ULL(input * (max - min), AMDGPU_MAX_BL_LEVEL);

}



static void convert_custom_brightness(const struct amdgpu_dm_backlight_caps *caps,

				      uint32_t *brightness)

				      unsigned int min, unsigned int max,

				      uint32_t *user_brightness)

{

	u32 brightness = scale_input_to_fw(min, max, *user_brightness);

	u8 prev_signal = 0, prev_lum = 0;

	int i = 0;
@@ -4734,7 +4748,7 @@ static void convert_custom_brightness(const struct amdgpu_dm_backlight_caps *cap 
		return;



	/* choose start to run less interpolation steps */

	if (caps->luminance_data[caps->data_points/2].input_signal > *brightness)

	if (caps->luminance_data[caps->data_points/2].input_signal > brightness)

		i = caps->data_points/2;

	do {

		u8 signal = caps->luminance_data[i].input_signal;
@@ -4745,17 +4759,18 @@ static void convert_custom_brightness(const struct amdgpu_dm_backlight_caps *cap 
		 * brightness < signal: interpolate between previous and current luminance numerator

		 * brightness > signal: find next data point

		 */

		if (*brightness > signal) {

		if (brightness > signal) {

			prev_signal = signal;

			prev_lum = lum;

			i++;

			continue;

		}

		if (*brightness < signal)

		if (brightness < signal)

			lum = prev_lum + DIV_ROUND_CLOSEST((lum - prev_lum) *

							   (*brightness - prev_signal),

							   (brightness - prev_signal),

							   signal - prev_signal);

		*brightness = DIV_ROUND_CLOSEST(lum * *brightness, 101);

		*user_brightness = scale_fw_to_input(min, max,

						     DIV_ROUND_CLOSEST(lum * brightness, 101));

		return;

	} while (i < caps->data_points);

}
@@ -4768,11 +4783,10 @@ static u32 convert_brightness_from_user(const struct amdgpu_dm_backlight_caps *c 
	if (!get_brightness_range(caps, &min, &max))

		return brightness;



	convert_custom_brightness(caps, &brightness);

	convert_custom_brightness(caps, min, max, &brightness);



	// Rescale 0..255 to min..max

	return min + DIV_ROUND_CLOSEST((max - min) * brightness,

				       AMDGPU_MAX_BL_LEVEL);

	// Rescale 0..max to min..max

	return min + DIV_ROUND_CLOSEST_ULL((u64)(max - min) * brightness, max);

}



static u32 convert_brightness_to_user(const struct amdgpu_dm_backlight_caps *caps,
@@ -4785,8 +4799,8 @@ static u32 convert_brightness_to_user(const struct amdgpu_dm_backlight_caps *cap 


	if (brightness < min)

		return 0;

	// Rescale min..max to 0..255

	return DIV_ROUND_CLOSEST(AMDGPU_MAX_BL_LEVEL * (brightness - min),

	// Rescale min..max to 0..max

	return DIV_ROUND_CLOSEST_ULL((u64)max * (brightness - min),

				 max - min);

}
@@ -4936,11 +4950,10 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector) 
		drm_dbg(drm, "Backlight caps: min: %d, max: %d, ac %d, dc %d\n", min, max,

			caps->ac_level, caps->dc_level);

	} else

		props.brightness = AMDGPU_MAX_BL_LEVEL;

		props.brightness = props.max_brightness = AMDGPU_MAX_BL_LEVEL;



	if (caps->data_points && !(amdgpu_dc_debug_mask & DC_DISABLE_CUSTOM_BRIGHTNESS_CURVE))

		drm_info(drm, "Using custom brightness curve\n");

	props.max_brightness = AMDGPU_MAX_BL_LEVEL;

	props.type = BACKLIGHT_RAW;



	snprintf(bl_name, sizeof(bl_name), "amdgpu_bl%d",