Some Small Progress On Linux GPU Laptop Switching
Phoronix: Some Small Progress On Linux GPU Laptop Switching
A few weeks ago we reported that notebook hybrid graphics switching on Linux still sucks. For these newer laptops that boast dual GPUs -- an integrated low-power IGP and a more performance-oriented discrete GPU for demanding environments with switching between the two being done "seamlessly" in real-time based upon usage or via a hot-key -- the support under Linux is still virtually nonexistent. There is a crude form of Linux GPU switching, but for the most part it's not nearly up to par for what's available in Microsoft Windows 7 or Apple Mac OS X. The situation remains that way, but some small progress has been made...
Does anyone know of any work on *desktop* GPU switching? Next year many or most desktop CPUs will have an integrated GPU, while discrete ones are more common than in laptops. It would be great to leverage that.
It's all the same problem more or less. To support it we need lots of infrastructural changes in the graphics stack. As Dave outlined at LPC, there are basically 4 multi-GPU scenarios that we want to be able to support eventually:
Originally Posted by Otus
1. crossfire (multiple GPUs rendering a single app)
2. hybrid laptops with a display mux
3. hybrid laptops (or desktops) without a display mux
4. single logical desktop over multiple similar cards with 3D
In a nutshell, we need to fix xinerama and randr to play together properly and add a mechanism to share buffers between kms drivers.
It'd be really nice if he'd get back to making the ATI/Intel switching work again, or at all in the first place. I'm tired of having to disable switching in the BIOS every time I boot into Linux.
One potential workaround is to create two entries in GRUB (or whatever you use), and in one entry enable ATI KMS by adding to the kernel boot options:
Originally Posted by siride
and enable intel KMS in the other with:
Then you can select at boot time which card you want to use. Of note, KMS restricts you from using ATI's official drivers, so if you actually want to use Linux for gaming or other 3d intensive tasks it's less than satisfactory. However, it does allow you to keep switching on in the BIOS.
Does that actually shut off the other card? That's my concern and my understanding for my machine (ThinkPad T500) is that the other card *won't* be turned off unless you disable it in the BIOS or use VGA switcheroo to do it. I don't want both cards on, producing eat and using power for naught.
Originally Posted by le grand fuzzy
I think that the end of hybrid notebooks is near or at least the third party implementations of switching between the cards, because of the appearance of the accelerating units as AMD's Fusion and Intel's Sandy Bridge where this type of switching should be implemented over low-level hardware or over BIOS. But it is really painful that there's no way to turn off the dedicated 3D when there's no need of it on the existing notebook computers with working solution on other closed-source platforms.
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