1002:6760 [Sony VAIO VPCSB2C5E] Power consumption higher after resume, probably vgaswitcheroo/radeon related

I noticed that the power consumption, as reported in

/proc/acpi/battery/BAT1/state

gets higher when I resume my laptop from suspend to RAM. I strongly suspect that this is related to a bug in vgaswitcheroo or the radeon driver, since the power used after resume is consistent with the power used when the discrete video card is not off.

Before resume I made sure the discrete card was off by using

sudo bash -c "echo OFF > /sys/kernel/debug/vgaswitcheroo/switch"

At resume, with high power consumption, the state is reported as expected:

sudo cat /sys/kernel/debug/vgaswitcheroo/switch
0:IGD:+:Pwr:0000:00:02.0
1:DIS: :Off:0000:01:00.0

Still, if I run:

sudo bash -c "echo ON > /sys/kernel/debug/vgaswitcheroo/switch"
sudo bash -c "echo OFF > /sys/kernel/debug/vgaswitcheroo/switch"

Now the power consumption goes down to the expected level.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image (not installed)
ProcVersionSignature: Ubuntu 3.2.0-26.41-generic 3.2.19
Uname: Linux 3.2.0-26-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu5
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: PCH [HDA Intel PCH], device 0: ALC275 Analog [ALC275 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: alex 2005 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'PCH'/'HDA Intel PCH at 0xc9400000 irq 51'
   Mixer name : 'Intel CougarPoint HDMI'
   Components : 'HDA:10ec0275,104d5000,00100005 HDA:80862805,104d5000,00100000'
   Controls : 26
   Simple ctrls : 10
Date: Sun Jul 22 01:23:17 2012
HibernationDevice: RESUME=UUID=6b1034dd-b958-4939-88b4-829282357ed6
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110930)
MachineType: Sony Corporation VPCSB2C5E
ProcFB:
 0 inteldrmfb
 1 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-26-generic root=UUID=d4bbd7c4-dc64-42f6-a165-073e9b828c86 ro pcie_aspm=force i915.i915_enable_rc6=1
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-26-generic N/A
 linux-backports-modules-3.2.0-26-generic N/A
 linux-firmware 1.79
SourcePackage: linux
StagingDrivers: rts_pstor mei
UpgradeStatus: Upgraded to precise on 2012-04-27 (85 days ago)
dmi.bios.date: 04/25/2011
dmi.bios.vendor: INSYDE
dmi.bios.version: R1031H4
dmi.board.asset.tag: N/A
dmi.board.name: VAIO
dmi.board.vendor: Sony Corporation
dmi.board.version: N/A
dmi.chassis.asset.tag: N/A
dmi.chassis.type: 10
dmi.chassis.vendor: Sony Corporation
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnINSYDE:bvrR1031H4:bd04/25/2011:svnSonyCorporation:pnVPCSB2C5E:pvrC609LHCC:rvnSonyCorporation:rnVAIO:rvrN/A:cvnSonyCorporation:ct10:cvrN/A:
dmi.product.name: VPCSB2C5E
dmi.product.version: C609LHCC
dmi.sys.vendor: Sony Corporation