From owner-freebsd-current@FreeBSD.ORG Wed Jan 28 07:23:28 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 F3D87B5D for ; Wed, 28 Jan 2015 07:23:27 +0000 (UTC) Received: from mail.wilcox-tech.com (mail.foxkit.us [192.99.209.192]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.wilcox-tech.com", Issuer "mail.wilcox-tech.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 904FB787 for ; Wed, 28 Jan 2015 07:23:26 +0000 (UTC) Received: (qmail 21058 invoked from network); 28 Jan 2015 07:24:30 -0000 Received: from c-71-57-141-247.hsd1.fl.comcast.net (HELO Todd) (AWilcox@Wilcox-Tech.com@71.57.141.247) by mail.foxkit.us with ESMTPA; 28 Jan 2015 07:24:30 -0000 From: "Andrew Wilcox" To: "'Ranjan1018 .'" <214748mv@gmail.com> References: <000e01d039fb$d5959930$80c0cb90$@Wilcox-Tech.com> In-Reply-To: Subject: RE: drm2 regression: backlight adjustment on ivybridge no longer works Date: Wed, 28 Jan 2015 01:23:26 -0600 Message-ID: <009501d03acb$4f380d70$eda82850$@Wilcox-Tech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQIkD3QRswOKHk1/aLD21PpFfsdgwgGR9mCRAv4GIYoBQ/0CWZv+1SDQ Content-Language: en-gb Cc: '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 07:23:28 -0000 Ranjan1018 . sent: 27 January 2015 23:42: > The regression was introduced in r277487. Looking closer at this revision, I believe I may see the issue. Most of = the new tunables introduced in dev/drm2/i915/i915_drv.c are = uninitialised and thus probably contain junk. It likely works for me = because the firmware of my laptop 0s memory on EFI boot. I have uploaded a diff here that I believe may fix this. Please test = and let me know: http://foxkit.us/FreeBSD/i915-uninitialised-var-fix.diff Best, Andrew -- Andrew Wilcox, C/C++/Python developer, kernel hacker Blog: http://blog.foxkit.us/ WWW: http://foxkit.us/ GitHub: https://github.com/awilfox