From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2061 invoked by alias); 26 Mar 2013 15:58:48 -0000 Mailing-List: contact cygwin-xfree-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-xfree-owner@cygwin.com Reply-To: cygwin-xfree@cygwin.com Mail-Followup-To: cygwin-xfree@cygwin.com Received: (qmail 1959 invoked by uid 89); 26 Mar 2013 15:58:42 -0000 X-Spam-SWARE-Status: No, score=2.3 required=5.0 tests=AWL,BAYES_50,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RP_MATCHES_RCVD autolearn=ham version=3.3.1 Received: from snt0-omc2-s29.snt0.hotmail.com (HELO snt0-omc2-s29.snt0.hotmail.com) (65.55.90.104) by sourceware.org (qpsmtpd/0.84/v0.84-167-ge50287c) with ESMTP; Tue, 26 Mar 2013 15:58:39 +0000 Received: from SNT402-EAS234 ([65.55.90.72]) by snt0-omc2-s29.snt0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Tue, 26 Mar 2013 08:58:38 -0700 X-EIP: [6NPQTjzQPEnwcTw2WASL0YsxaZ0WqOTk9ro3iDMNv+s=] Message-ID: Reply-To: From: "Aaron A. Kelley" To: Subject: Cygwin/X causes NVIDIA GPU to turn on in Optimus systems Date: Tue, 26 Mar 2013 15:58:00 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-SW-Source: 2013-03/txt/msg00017.txt.bz2 For those that aren=92t aware, NVIDIA Optimus is a feature that makes use of the Intel GPU that is included in new Intel Core i series processors (Sandy Bridge and up).=A0 Basically, in a system that has both the integrated Intel GPU and also a discrete NVIDIA GPU, the Intel GPU is used for most desktop operations and the NVIDIA GPU kicks in when the graphics power is needed for games and other processing jobs.=A0 This is done to save power --- if the NVIDIA GPU can spend most of its time powered down, your battery lasts longer.=A0 The NVIDIA card can be used to run only particular applications individually, and its output is dumped over to the Intel GPU for display using some fast framebuffer magic. I usually leave Cygwin/X open on my machine because I use it to access GUI apps running in SSH terminals from time to time.=A0 Today I noticed that in= an Optimus environment, it is causing the NVIDIA GPU to kick in, which causes the NVIDIA GPU to stay powered on when maybe it doesn=92t need to. http://stuff.aaron-kelley.net/2013/03/cygxoptimus.png I went to the NVIDIA control panel and set xwin.exe specifically to use the integrated GPU but it still says that xwin.exe is running on the NVIDIA GPU when I run it.=A0 Cygwin/X must be doing something unusual at initialization that makes the NVIDIA card feel like it has to kick on.=A0 I don=92t have to actually launch any X windows to see this occur, it happens moments after I launch the Cygwin/X server. I haven=92t been able to find anyone else mentioning this.=A0 It may be bec= ause Optimus configurations aren=92t very common.=A0 This also means that this i= ssue may be tricky to track down.=A0 I=92m not sure if it will be easy to find someone who knows about Cygwin/X development who also has access to an Optimus environment.=A0 This might be something that has to go for NVIDIA f= or them to fix in their drivers, but it=92d be nice to know a little more about the issue before trying to get in touch with them. I=92m interested in doing anything I can do help address this but I don=92t= know where to begin, so I=92m welcoming your feedback. Thanks, --=20 Aaron -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://x.cygwin.com/docs/ FAQ: http://x.cygwin.com/docs/faq/