need to turn off extra "Switchable graphics" GPU

Bug #435906 reported by Tuukka Hastrup on 2009-09-24
This bug affects 14 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Nominated for Dapper by dani
Nominated for Hardy by dani
Nominated for Intrepid by dani
Nominated for Jaunty by dani
Nominated for Karmic by Tuukka Hastrup
Nominated for Lucid by dani
Nominated for Maverick by Sunny

Bug Description

Some laptops such as this Acer Travelmate 8371G (Timeline) have two graphics adapters (Intel 4500MHD and ATI HD 4330). There are two BIOS settings: "Switchable graphics" and "Discrete graphics". With the latter option, only the ATI GPU is in use, but with the former option, *both* GPUs are powered on by default. Neither of these options is good for battery runtime.

Fortunately, Maverick kernel has the vga_switcheroo module enabled and it supports this laptop. What's missing by default is the command "echo OFF > /sys/kernel/debug/vgaswitcheroo/switch", which is needed to turn off the discrete GPU.

On the 8371G here, "Switchable graphics" originally gave some 2 hours of battery use, "Discrete graphics" gives some 3 hours of battery use, and "Switchable graphics" with this module loaded gives some 4 hours of battery use.

ProblemType: Bug
Architecture: i386
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
 /dev/snd/controlC0: tuukka 1878 F.... pulseaudio
CRDA: Error: [Errno 2] Tiedostoa tai hakemistoa ei ole
 Card hw:0 'Intel'/'HDA Intel at 0xf4500000 irq 22'
   Mixer name : 'Realtek ALC269'
   Components : 'HDA:10ec0269,10250284,00100004'
   Controls : 21
   Simple ctrls : 12
Date: Thu Sep 24 16:28:44 2009
DistroRelease: Ubuntu 9.10
HibernationDevice: RESUME=UUID=3a0cc818-d22b-4df4-9947-61373f45494c
MachineType: Acer TravelMate 8371
Package: linux-image-2.6.31-10-generic 2.6.31-10.35
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.31-10-generic root=UUID=58fdc759-1719-40df-b6b6-1902991b8bba ro quiet splash
 PATH=(custom, user)
ProcVersionSignature: Ubuntu 2.6.31-10.35-generic
 linux-backports-modules-2.6.31-10-generic N/A
 linux-firmware 1.19
SourcePackage: linux
Uname: Linux 2.6.31-10-generic i686 08/05/2009
dmi.bios.vendor: Acer
dmi.bios.version: V1.11
dmi.board.asset.tag: Base Board Asset Tag TravelMate 8371
dmi.board.vendor: Acer
dmi.board.version: PSMBOU-1234567
dmi.chassis.asset.tag: None
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: None
dmi.modalias: dmi:bvnAcer:bvrV1.11:bd08/05/2009:svnAcer:pnTravelMate8371:pvrV1.11:rvnAcer:rnTravelMate8371:rvrPSMBOU-1234567:cvnAcer:ct10:cvrNone: TravelMate 8371
dmi.product.version: V1.11
dmi.sys.vendor: Acer

Tuukka Hastrup (tuukkah) wrote :
Mansour Behabadi (oxplot) wrote :

I confirm this on my Travelmate 8371G. However, I constantly get over 5 hours of battery life. Without the module, <2 hours on Switchable mode and ~3 hours on Discrete mode with Powerplay option of ATI proprietary driver.

Changed in linux (Ubuntu):
status: New → Confirmed
Albert Vilella (avilella) wrote :

You can possibly use the code from asus_nvidia.c in the link below that has resume from hibernation support for the Asus UL30Vt/UL50V/UL80V:

Albert Vilella (avilella) wrote :

For those with "G" Timeline models (with discrete ATI card),

David Airlie has posted v11 of his vga-switcheroo patch:

You can use the excellent howto here:

Sunny (wickedsunny-3) wrote :

I have an ATI graphics and integrated Intel graphics and the modes under windows is determined by the powered mode. I can not boot into linux from a live cd as i can not see the desktop. The welcome sound is heard but there is no graphics. All I can see is a black screen. My laptop is a HP Pavilion DV6-3006TX.

Tuukka Hastrup (tuukkah) wrote :

Now in Maverick, vga_switcheroo is enabled, but the extra GPU is still powered on by default.

As a workaround, I've added the following line to /etc/rc.local:

  echo "OFF" > /sys/kernel/debug/vgaswitcheroo/switch

Tuukka Hastrup (tuukkah) on 2010-11-11
description: updated
Adam Niedling (krychek) wrote :

Why is this not a duplicate of bug #312756 ?

Tuukka Hastrup (tuukkah) wrote :

Adam, wrt bug #312756 "support graphics card hot switch":

Here in bug #435906, I'm not asking for hot switch -- what we urgently need is just that the extra GPU be turned off. I consider this a significant bug as these laptops are certainly not designed to power two GPUs at a time. Further, this is not something very complicated so I would've hoped for a fix earlier. It's even easier now that it's a one-liner :-)

Adam Niedling (krychek) wrote :

If it would be possible to switch between graphics cards then consequently it would also be possible to turn off the one you don't need. It seems like there is a lot of effort being made for the master bug, I don't think another project will start just for this one as this is just a subset of the main project.
What makes you think this is just a one-liner? There are many different laptops with many different graphics cards.

This bug was filed against a series that is no longer supported and so is being marked as Won't Fix. If this issue still exists in a supported series, please file a new bug.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu):
status: Confirmed → Won't Fix
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