The Acer i5 laptop comes with two graphics paths :
The i5 associated (Intel) chipset, and
A ‘discrete’ nVidia GT 750M / 4Gb graphics card (which looks like the more interesting OpenCL device)
One issue, though, is that the Intel graphics chip is low-power, and I love the ~7hr battery life. Whereas running the NVidia card (according to people on the internet) reduces the laptop battery life to 1.5hr.
So, it’s important to be able to switch the NVidia card on only when necessary (which is what the ‘Optimus’ technology apparently does on Windows).
To get the device driver installed for the NVidia card, here are the basic steps (ignore the first two) :
Fiddle around with doing it the hard way (install from souce download)
Try something promising-looking
Cave in and do it the best way :
Cutting a long story short, the hard way uncovered the fact that the new kernel driver needs signing to work with
UEFI. But that’s tricky.
Disable Secure Boot (on Acer)
So I disabled Secure Boot (no matter, at least for now : I don’t feel too insecure, being on a laptop with few internet-facing services).
See : http://acer–uk.custhelp.com/app/answers/detail/a_id/27071/~/how-to-enable-or-disable-secure-boot
To fix this (so that it survives reboot), edit
Doing the NVidia install the Bumblebee way
Before the process
lsmod | tail gives :
Then do the bumblebee install :
To force a recompilation on the next reboot :
Once it’s correctly installed,
modinfo nvidia will produce something like (notice that the same instructions also work for Fedora 21…) :
But where is the driver ?
Importantly, on boot, Bumblebee doesn’t install the new driver immediately.
Here’s my (meagre) understanding of how it works :
When you require the NVidia Graphics card (specifically, when you run an
optirun GRAPHICS-PROGRAM on the command line) the bumblebee system appears to load the
nvidia driver into the kernel, and tell it that it’s in control of a small screen (which matches the dimensions of X application you’re running). By the magic of X, the graphics card is none-the-wiser, and bumblebee then ‘takes a picture’ of the application at 60fps, and slaps it on the actual screen (still run by the Intel graphics chip).
Can this run OpenCL graphics coprocessor jobs?
Yes : Definitely. It can also run CUDA stuff too, if you install the CUDA SDK (not necessary for plain OpenCL).
There’s a problem getting the Nvidia card to wake up after a suspend, apparently. See my update post to resolve it with a suspend-hook workaround.
- Nvidia (22)
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- linux (71)
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- fc21 (5)
- Acer (3)
- Optimus (3)
- bumblebee (5)
- GT-750M (2)
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