Getting there Re: Current support and roadmap for discrete graphics card hot switching

Albert Vilella avilella at
Fri Feb 20 11:09:06 PST 2009

Hi all,

Just to give a heads up to everyone interested in this thread, one of
the Sony Vaio Z-series launchpad team members has found a way to turn
on/off the discrete nvidia graphics card by investigating the DSDT
tables. So we have at least 60 happy users that can enjoy this feature
now. Details here:

The mode can be switched through sysfs:

    echo stamina > /sys/devices/platform/sony-laptop/speed_stamina
 echo speed > /sys/devices/platform/sony-laptop/speed_stamina

Make sure you have no X server running while doing this, as X will break.

The drivers starts in stamina mode as default. This can be changed by
a parameter, to startup in speed mode:

  insmod sony-laptop speed_stamina=1

It is unsure initialisation of the Nvidia card is complete and this
has not been tested. Loading such a module at boot time might break
your linux installation (or at least making it impossible to start up
the X server).
Unfortunately the PCI system doesn't really recognize the change and
still shows the 00:02.0 Intel graphics controller and the 01:00.0
Nvidia graphics controller, but not the 00:02.1 Intel card. So if you
use scripts to switch your config, this will break.

I guess it's a matter of picking up from here now, trying to get
this to work better with a running X server somehow.



On Thu, Jan 15, 2009 at 10:21 AM, Albert Vilella <avilella at> wrote:
> Hi all,
> What is the current support and roadmap for discrete graphics card hot
> switching in Xorg?
> See:
> Hybrids with the Ability to turn off the 3d chip:
> AMD/ATI calls it PowerXpress and Nvidia HybridPower. It uses 2 graphics
> cards, one energy efficient with little 3d power and the other for gaming
> (fast and uses more/a lot of power), the user can choose which chip to use.
> This is not a new concept. Sony has build in 2 graphics chips into some of
> their laptops for years. In the past a reboot was required to switch between
> the chips. With the new generation it is possible to change between chips on
> the fly, the screen will flicker but no need to reboot. At least in Windows
> Vista (XP, Linux not supported) the user can switch freely between the chips
> or set up a profile to do so automatically (eg when on battery use low power
> chip and when plugged in use the more powerful chip).
> The graphic card hybrid not only works with two Nvidia or AMD cards but the
> low power Intel graphics solutions (mostly shard memory) can also be
> combined with 3d chips from AMD or Nvidia. This solution is ideal for users
> who want maximum battery life and be able to play current games. The most
> likely combination is Intel shard memory graphics card for battery life and
> some low to mid level 3d chip. This will not give great 3d performance but
> enable you to play some games.
> Limitations are the drivers. Special drivers are needed depending on which
> graphic chips are combined in the hybrid. This will most likely make you
> depended on the Notebook manufactures driver support. It is uncertain if 3rd
> party drivers (such as laptopvideo2go) will be usable.
> One of the models is the Sony Vaio Z series. Right now, both cards are
> visible under Linux, but there is no way to hot-switching-off (if that is a
> word...) the Nvidia card. For a summary of users' experimentation with this
> laptop and Linux.
> There are currently ~40 users of Sony Vaio Z series using Linux that would
> like this feature to be implemented. See:
> Also, see:
> Thanks,
>     Albert.

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