From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA2BA22069F; Thu, 3 Jul 2025 15:09:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751555360; cv=none; b=V3HE0jSjpWqEiOO6V0UBfKRxtyn7X+KmV6xE2GDzxCganJcWIKMIeAGGdM8tFL3q9b2rEmxu/vpQ5uTCLi/uASMuvglPZ2Eukpt+wzcA1ri6215iTAZYswywJE3sKpQxoxsMGIYMOv3D0l10JJJqtqxS74xOXYpOVen+AxZ4pLE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751555360; c=relaxed/simple; bh=0fqBu1PBjNDxLo/WKH/kPy5FBsz19THuvrYyd5sSCYc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JF9s8xwBpyX/NxLZi/aJY+5p+bhb2J0txMSBfotMaqdPrHq26XccZ+SHiIccOuDkBZNLiZRibtWffzWjfIObjo7aKUzCPnCHurrSELSt+DMBn6jj2kfkuA3fdWKSDT7MKffrZg/lI6PuKQ61FZYdvx+cSxTCzFtknHULbWF7BRM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=exuXLv8+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="exuXLv8+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E86FEC4CEE3; Thu, 3 Jul 2025 15:09:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751555360; bh=0fqBu1PBjNDxLo/WKH/kPy5FBsz19THuvrYyd5sSCYc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=exuXLv8+iHDeiCWAdo1N7QZrywn5UCcVODt5g8o6le9pqLZo0YnGF52gZnach8E8s URckOO0djqJfq0unTDpsoS+i7eQI5CMWSIJwlE99mB8XyY/CDmibCFOrffeLCtCj/d yXcaRy777ytL5P3Ykck9Y3e6AH8N/P1Ga1KHgVd8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mario Limonciello , Alex Deucher , Roman Li , Alex Hung , Daniel Wheeler Subject: [PATCH 6.15 253/263] drm/amd/display: Export full brightness range to userspace Date: Thu, 3 Jul 2025 16:42:53 +0200 Message-ID: <20250703144014.556357863@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250703144004.276210867@linuxfoundation.org> References: <20250703144004.276210867@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mario Limonciello [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 Cc: Alex Deucher Reviewed-by: Roman Li Signed-off-by: Mario Limonciello Signed-off-by: Alex Hung Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 8dbd72cb790058ce52279af38a43c2b302fdd3e5) Cc: stable@vger.kernel.org --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 41 ++++++++++++------- 1 file changed, 27 insertions(+), 14 deletions(-) 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 a9a719f051f90..c5c2f82448f21 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -4655,9 +4655,23 @@ 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; @@ -4668,7 +4682,7 @@ 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; @@ -4679,17 +4693,18 @@ 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); } @@ -4702,11 +4717,10 @@ 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, @@ -4719,8 +4733,8 @@ 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); } @@ -4870,11 +4884,10 @@ 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", -- 2.39.5