On Mon, 2011-05-16 at 14:27 +0200, Christof Damian wrote: > On Mon, May 16, 2011 at 12:47, Matej Cepl <mcepl@xxxxxxxxxx> wrote: > > Dne 14.5.2011 23:23, Andreas Tunek napsal(a): > >> If I understand correctly, my computer (2011 27 inch iMac) has an > >> integrated intel GPU, but Fedora is using the Radeon GPU. Is there any > >> way what GPU you use? I did not find any documentation regarding this, > >> but maybe I looked at the wrong places? > > > > With Thinkpad T400 (ATI/Intel dual graphics) I could theoretically (it's > > broken on my machine) switch the GPU in BIOS. There is almost certainly > > nothing in Linux drivers to do so. > > I can switch GPUs in my T510 with switcheroo, which is included in > Fedora already. > > See: http://en.gentoo-wiki.com/wiki/Vga_switcheroo and > http://christof.damian.net/2010/11/fedora-14-on-lenovo-thinkpad-t510.html?showComment=1291238658612#c255706088919254379 > > Not sure if this applies to the iMac Doing it in the BIOS, if possible, I would expect to be more reliable and probably also more efficient. All implementations differ slightly, but usually if you have an option to 'lock' one card in the BIOS, it will completely disable the other; this is how it works on my Sony Vaio Z. This probably saves power as the other chipset is completely disabled, and makes things rather simpler for the kernel and X because they don't have to handle two chipsets at all, the system just looks like a perfectly normal, single-chipset one. I've also observed before that, if you can manage it, disabling the 'faster' chipset and using the Intel one permanently is almost always going to be the best approach on Linux, because the proprietary drivers don't work with these systems and the free drivers for the Radeon and NVIDIA chipsets are likely to be slower and buggier than the ones for the Intel chipsets, even if the Radeon/NVIDIA chips are _theoretically_ more powerful. So there's just about nothing to gain from trying to use them as 'intended' - running with the Radeon/NVIDIA chip will probably only make the system buggier, hotter, slower, and more power-hungry. IMBW, but my take is it's best to try and find a way to lock the system into the Intel chipset, and just use that; and that's usually going to be in the BIOS. (For my Sony, I had to hack the BIOS to expose the necessary option; this is pretty well documented in various forums. I don't know about Macs.) -- Adam Williamson Fedora QA Community Monkey IRC: adamw | Fedora Talk: adamwill AT fedoraproject DOT org http://www.happyassassin.net -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
