Using Ubuntu 13.04 and Nvidia 325.x driver from the Xorg-edgers PPA, I don't see any issue anymore.
Also make sure not to use any brightness fixing methods which seem to be needed with Nvidia proprietary driver < 325. So, remove any of the acpi_osi=Linux
and acpi_backlight=vendor
kernel parameters, otherwise bbswitch
will complain about a missing ACPI handle for the discrete graphics card and won't be able to actually switch graphics.
With acpi_backlight=vendor
(idle power consumption 22W+):
Sep 2 01:17:59 gert kernel: [ 12.999284] bbswitch: Found integrated VGA device 0000:00:02.0: \_SB_.PCI0.GFX0
Sep 2 01:17:59 gert kernel: [ 12.999292] bbswitch: Found discrete VGA device 0000:01:00.0: \_SB_.PCI0.PEG0.VID_
Sep 2 01:17:59 gert kernel: [ 12.999782] bbswitch: failed to evaluate \_SB_.PCI0.GFX0._DSM {0xA0,0xA0,0x95,0x9D,0x60,0x00,0x48,0x4D,0xB3,0x4D,0x7E,0x5F,0xEA,0x12,0x9F,0xD4} 0x102 0x0 {0x00,0x00,0x00,0x00}: AE_NOT_FOUND
Sep 2 01:17:59 gert kernel: [ 12.999785] bbswitch: No suitable _DSM call found.
Sep 2 01:17:59 gert bumblebeed[1953]: Module bbswitch could not be loaded (timeout?)
Without acpi_backlight=vendor
(idle power consumption 10-11W):
Sep 2 08:23:53 gert kernel: [ 9.609896] bbswitch: Found integrated VGA device 0000:00:02.0: \_SB_.PCI0.GFX0
Sep 2 08:23:53 gert kernel: [ 9.609901] bbswitch: Found discrete VGA device 0000:01:00.0: \_SB_.PCI0.PEG0.VID_
Sep 2 08:23:53 gert kernel: [ 9.610153] bbswitch: detected an Optimus _DSM function
Sep 2 08:23:53 gert kernel: [ 9.610168] bbswitch: Succesfully loaded. Discrete card 0000:01:00.0 is on
Sep 2 08:23:53 gert kernel: [ 9.611411] bbswitch: disabling discrete graphics
The upgrade to 13.04 also fixed other minor issues and it seems the machine is running a lot better now in terms of power management.