From owner-freebsd-questions@freebsd.org Wed Feb 10 17:15:03 2021 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 7EDE854D20D for ; Wed, 10 Feb 2021 17:15:03 +0000 (UTC) (envelope-from pete@nomadlogic.org) Received: from mailman.nyi.freebsd.org (unknown [127.0.1.3]) by mx1.freebsd.org (Postfix) with ESMTP id 4DbRGH26svz4myF for ; Wed, 10 Feb 2021 17:15:03 +0000 (UTC) (envelope-from pete@nomadlogic.org) Received: by mailman.nyi.freebsd.org (Postfix) id 48B9E54D136; Wed, 10 Feb 2021 17:15:03 +0000 (UTC) Delivered-To: questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4869354D362 for ; Wed, 10 Feb 2021 17:15:03 +0000 (UTC) (envelope-from pete@nomadlogic.org) Received: from mail.nomadlogic.org (mail.nomadlogic.org [174.136.98.114]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "mail.nomadlogic.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4DbRGG6mRdz4n8v for ; Wed, 10 Feb 2021 17:15:02 +0000 (UTC) (envelope-from pete@nomadlogic.org) Received: from [192.168.1.160] (cpe-24-24-163-126.socal.res.rr.com [24.24.163.126]) by mail.nomadlogic.org (OpenSMTPD) with ESMTPSA id e2efcedd (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 10 Feb 2021 17:15:01 +0000 (UTC) Subject: Re: Brightness cannot be set on Lenovo L15 ThinkPad To: Kevin Oberman , "freebsd-questions@freebsd.org" References: From: Pete Wright Message-ID: <220cabf0-14ce-88b6-fc33-14c650607e1b@nomadlogic.org> Date: Wed, 10 Feb 2021 09:15:00 -0800 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Rspamd-Queue-Id: 4DbRGG6mRdz4n8v X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Feb 2021 17:15:03 -0000 On 2/9/21 9:31 PM, Kevin Oberman wrote: > I can only guess that this may be an ACPI issue. > > I recently (last week) replaced my decade old T520 with a new ThinkPad L15 > with a 10th gen I5 CPU (Tiger Lake). I have everything working except the > WiFi (which I knew would not work) and setting brightness on the display. > > I have loaded acpi_ibm and it returns '0' for brightness. I tried > intel-backlight, which shows the brightness to be '0'. It does nothing, > either. > > I thought that I read that drm-fbsd13-kmod had the ability to do the job, > but I have no idea how to do anything with it. I do see sysctls for > hw.i915kms.enable_dpcd_backlight and invert_brightness, but I still have no > clue whether they are relevant. > > Any suggestions would be greatly appreciated! Hey there Kevin, I have a Thinkpad P43s with working backlight - on my end I load the both the acpi_ibm and acpi_video kernel modules.  One interesting nit is that I have to load the ibm kmod *before* the video kmod or things don't work.  Here's my kld_list from rc.conf: kld_list="cpuctl /boot/modules/i915kms.ko acpi_ibm acpi_video filemon" i also set my default brightness via sysctl.conf like so: hw.acpi.video.lcd0.brightness=40 My reading of the man pages is that acpi_ibm is used to enable the function keys to control brightness, volume control etc and acpi_video does manages the backlight brightness itself. Hope this helps, -pete -- Pete Wright pete@nomadlogic.org @nomadlogicLA