From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6CCBFCD3430 for ; Mon, 4 May 2026 13:56:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8BC0E10E6F3; Mon, 4 May 2026 13:56:38 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=bootlin.com header.i=@bootlin.com header.b="pThgDbKm"; dkim-atps=neutral Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) by gabe.freedesktop.org (Postfix) with ESMTPS id E493F10E6F3 for ; Mon, 4 May 2026 13:56:36 +0000 (UTC) Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id 838CC4E42BB8; Mon, 4 May 2026 13:56:35 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 516165FD5F; Mon, 4 May 2026 13:56:35 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 9DDF011AD220E; Mon, 4 May 2026 15:56:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1777902994; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references; bh=j2hlp/6clsIxKcAavYQrD4NChynsESijBX8RXRMkRwA=; b=pThgDbKms2NLA13+nZwLI0zzAbBOv4c7xNMChf/jBC1L3Ti+emr2sjMLS7nGTthUQGAwfX p6v4gpem7omcsdsugaXdBttI8LwFWcni8wDNLJePTIwdCtenveRJLstlrMbCi1OxQf5b3O mEuWLS56s81cXLPBRJaGwzMGR0VTl2DCfQGt3C3xfxsyqqcCjLvxfMquikkY0nL+XI0vfo L62XI313cgOYk/ergTA27+RCHSTpHJPzf5rTtAHxHYO/admrH+ca/sXbD/H0vIxpn6OC56 xIwpA7odUJwMG6W6OHYTK/JNzvd7GaetxzSYCK6Vm5CPiClCf1lmhc+Mjg3zzw== Message-ID: <0f5cf41c-99d5-4427-86fe-18c4f1e2c95e@bootlin.com> Date: Mon, 4 May 2026 15:55:52 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 0/8] Add support for a DRM backlight capability To: Mario Limonciello , dri-devel@lists.freedesktop.org Cc: harry.wentland@amd.com, Xaver Hugl , amd-gfx@lists.freedesktop.org, Mario Limonciello References: <20260424220953.167058-1-mario.limonciello@amd.com> From: Louis Chauvet Content-Language: en-US In-Reply-To: <20260424220953.167058-1-mario.limonciello@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 4/25/26 00:09, Mario Limonciello wrote: > From: Mario Limonciello (AMD) > > At Display Next Hackfest 2025 we discussed the renewed need for moving > brightness control into the DRM connector properties. I've taken the > previous efforts from David and Marta, rebased and adjusted for the > current kernel. > > The legacy sysfs interface is synchronized with the DRM connector (although > the scale may be different as DRM connector property is u16). > > Later after this has been adopted by enough userspace, it may make sense to > configure the legacy sysfs interface to be configurable so that only > DRM master controls backlight. > > I've done a first implementation with amdgpu with eDP connectors; but > conceivably this can be extended to other connectors like DP for displays > that can be controlled via DDC as well later. > > I have also used DRM review prompts to review this series and fix some bugs > which were caught with two different Claude models. The fixes are squashed > into the patches. > > Assisted-by: Claude Opus > Assisted-by: Claude Sonnet > > For ease of testing; this series is also available on this branch: > https://git.kernel.org/pub/scm/linux/kernel/git/superm1/linux.git/log/?h=superm1/backlight-property-v3 Hello, thanks for this work, I am very interested in this progress so I can help you to test / implement more features. I think you forgot to include the revert of "backlight: Remove notifier" in your series, it can't be applied without it. I will take a look and see if I can create a VKMS implementation of your work. Thanks for this work, > David Rheinsberg (1): > backlight: add kernel-internal backlight API > > Mario Limonciello (6): > drm: link connectors to backlight devices > DRM: Add support for client and driver indicating support for > luminance > drm/amd/display: Pass up errors reading actual brightness > drm/amd: Indicate driver supports luminance > drm/amd/display: Allow backlight registration to fail > drm/amd/display: use drm backlight > > Marta Lofstedt (1): > backlight: expose the current brightness in the new kernel API > > drivers/gpu/drm/Kconfig | 1 + > drivers/gpu/drm/Makefile | 2 + > drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 1 + > .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 88 +++- > drivers/gpu/drm/drm_atomic_uapi.c | 24 ++ > drivers/gpu/drm/drm_backlight.c | 406 ++++++++++++++++++ > drivers/gpu/drm/drm_connector.c | 12 + > drivers/gpu/drm/drm_drv.c | 8 + > drivers/gpu/drm/drm_ioctl.c | 10 + > drivers/gpu/drm/drm_mode_config.c | 7 + > drivers/gpu/drm/drm_mode_object.c | 66 ++- > drivers/gpu/drm/drm_sysfs.c | 54 +++ > drivers/video/backlight/backlight.c | 83 ++++ > include/drm/drm_backlight.h | 45 ++ > include/drm/drm_connector.h | 8 + > include/drm/drm_drv.h | 7 + > include/drm/drm_file.h | 8 + > include/drm/drm_mode_config.h | 5 + > include/linux/backlight.h | 30 ++ > include/uapi/drm/drm.h | 10 + > 20 files changed, 852 insertions(+), 23 deletions(-) > create mode 100644 drivers/gpu/drm/drm_backlight.c > create mode 100644 include/drm/drm_backlight.h >