For those that arent 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). 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. This is done to save power --- if the NVIDIA GPU can spend most of its time powered down, your battery lasts longer. 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. 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 doesnt 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. Cygwin/X must be doing something unusual at initialization that makes the NVIDIA card feel like it has to kick on. I dont have to actually launch any X windows to see this occur, it happens moments after I launch the Cygwin/X server. I havent been able to find anyone else mentioning this. It may be because Optimus configurations arent very common. This also means that this issue may be tricky to track down. Im not sure if it will be easy to find someone who knows about Cygwin/X development who also has access to an Optimus environment. This might be something that has to go for NVIDIA for them to fix in their drivers, but itd be nice to know a little more about the issue before trying to get in touch with them. Im interested in doing anything I can do help address this but I dont know where to begin, so Im welcoming your feedback. Thanks, -- 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/