From owner-freebsd-current@FreeBSD.ORG Wed Jan 28 09:20:13 2015 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 417D3691; Wed, 28 Jan 2015 09:20:13 +0000 (UTC) Received: from mail-ie0-x230.google.com (mail-ie0-x230.google.com [IPv6:2607:f8b0:4001:c03::230]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 022093E6; Wed, 28 Jan 2015 09:20:13 +0000 (UTC) Received: by mail-ie0-f176.google.com with SMTP id rd18so20507241iec.7; Wed, 28 Jan 2015 01:20:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=YWbfTQqDwG+po4S2GdTmlxSxAp3kCDMUatx9vQHfjRc=; b=aQFCsbznjZM9NDEtKPFCtZpae9LVsTcNaDcIL5mXHzRx+sRYGp7fOT6jDDuwZBUeVh /mtUVPdd9niVqq4c8v30EDqkMOrmGx4HmrCporyVZ7jGjVNv4/Y7GFnKs/T8MkqEDmZK GSriIEF+k4p3kh/BtvD5Dc12X3uC4nKaM4VnexLc5+FRNjfz8JEYcrIdg7Wje9vz+ZdO KPQn+KQXQEgusfg0taGi/r4Dsh18+N1mCMvlnVJlYArvymWoRp7ZeKzTN3+8HvyPLk3W jCWnBKBRjQHHxXAfNC8/kRdRz9JL5vDQY1rCsL1HUE7r+sYw6JbTWoIVWdzO5kwuHmIC K9fQ== MIME-Version: 1.0 X-Received: by 10.50.164.227 with SMTP id yt3mr2420600igb.32.1422436812407; Wed, 28 Jan 2015 01:20:12 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.36.78.14 with HTTP; Wed, 28 Jan 2015 01:20:12 -0800 (PST) In-Reply-To: References: <000e01d039fb$d5959930$80c0cb90$@Wilcox-Tech.com> <009501d03acb$4f380d70$eda82850$@Wilcox-Tech.com> Date: Wed, 28 Jan 2015 01:20:12 -0800 X-Google-Sender-Auth: CTg8tvfMWzEksrE67rYKgojYDs8 Message-ID: Subject: Re: drm2 regression: backlight adjustment on ivybridge no longer works From: Adrian Chadd To: Andrew Wilcox , Konstantin Belousov Content-Type: text/plain; charset=UTF-8 Cc: "Ranjan1018 ." <214748mv@gmail.com>, freebsd-current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Jan 2015 09:20:13 -0000 and the commit from linux: commit 7aa1e7f06d6ea1bce3b27630d50769d13da28b1a Author: Daniel Vetter Date: Wed Jun 27 16:43:36 2012 +0200 Revert "drm/i915: allow PCH PWM override on IVB" This reverts commit f82cfb6bcda164ef3a66b8c3fc549b1f9bdd09ad. This breaks the backlight controls on my IVB asus zenbook with an eDP panel. I guess the right fix would be to read this bit and use either the pch or the cpu register to frob the backlight values. But that is stuff for -next. Cc: Jesse Barnes Signed-Off-by: Daniel Vetter On 28 January 2015 at 01:11, Adrian Chadd wrote: > ugh, so because i can't sleep, I read the Linux i915 history for > backlight changes. > > Turns out if I disable bit 30 in ivb_pch_pwm_override() to register > BLC_PWM_PCH_CTL1, the acpi video setting works. The keyboard settings > still don't, but I'll worry about that later. > > Bit 30 in the linux drm code is: > > #define BLM_PCH_OVERRIDE_ENABLE (1 << 30) > > The linux dri code doesn't set that for ivybridge - only for broadwell. > > (also, the linux driver has POSTING_READ() which I'm guessing is to > ensure things made it out to the device and have been flushed before > doing another IO operation.) > > I have my (via sysctl) panel backlight control working again. > > > > -adrian