On Thu, Jan 15, 2009 at 12:22, Albert Vilella <avile...@gmail.com> wrote: >>> There is no support, and AFAIK no roadmap either. There are many >>> technical reasons why this is not possible today. In short, I wouldn't >>> suggest getting a dual GPU laptop with the purpose of using it under >>> linux, as one of the GPUs will probably stay unused. > > Just to clarify the current situation: in some laptops, like Sony Vaio > models (SZ-series, Z-series), this feature is "partially" working: > > One can do a cold reboot: using the hardware stamina/speed switch in the > laptop to switch off the discrete > graphics card (Nvidia) at BIOS time. But the latest models (Z-series) allow > for a hot switch, right now only in Windows Vista. > If one installs Linux on these, both the Nvidia and the Intel will appear in > lspci, but xorg will not be able to handle both, > and the Nvidia hardware will be wasting battery and not being used. > Some people has managed to revert back to the cold reboot feature by > installing Windows XP on the laptop, > then switching on/off the discrete graphics card at BIOS time.
This is not what you'd call support. This is just the bios exposing a single graphics card. As far as X.Org is concerned, there is only one graphics card at a time. > > So the next step is the hot switch. My hunch is that Windows Vista does some > sort of "gdm restart" equivalent, > by the looks of this video on computer.tv: > > Jump to 4:10 for the switching bit: > > http://www.youtube.com/watch?v=Qcvu2Aluy7g > > This machine is the successor of the SZ premium series, and has a Dynamic > Hybrid Graphics system that will enable/disable the nvidia graphics card > using a software "hot" switch instead of a hardware "cold" switch (SZ > series). > > http://vaio-online.sony.com/prod_info/series1/z/interview_Z/index_05.html > > Can I ask someone who is expert enough in xorg to give a list of > blockers/things to try for this to happen, so that people can play with? > For example, people has been investigating BiosBase on the Nvidia side of > things: > > http://avilella.googlepages.com/vaioz (look for BiosBase) > http://bugs.freedesktop.org/show_bug.cgi?id=2597#c37 > Basically, we lack : - documentation on how to switch GPUs at the laptop level (i.e. do what the bios does at boot when you choose the card in the bios) - documentation on cold booting the nvidia GPU - driver support on both sides implementing proper GPU power up/shut down (we're talking about something big here) and if you want to keep your session in between, we lack - X.Org infrastructure to hand a session from a graphics driver to another (there are a million of possible problems here) - drivers supporting said infrastructure (we're talking about something real huge here) IMO all this is not very likely to happen. When you buy a laptop on which you want to run linux, I really suggest you check hardware compatibility. This is no different than unsupported wifi chips. Stephane _______________________________________________ xorg mailing list xorg@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/xorg