Messages in this thread | | | Date | Wed, 16 Sep 2009 12:33:58 -0400 | Subject | Re: Explicitly putting a PCI device to ACPI D0 | From | Alex Deucher <> |
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On Wed, Sep 16, 2009 at 12:09 PM, Jesse Barnes <jbarnes@virtuousgeek.org> wrote: > On Wed, 16 Sep 2009 09:10:24 +0200 > Michal Witkowski <neuro@o2.pl> wrote: > >> Hi, >> >> I've been searching for my answer for a while now, and since I >> haven't found it anywhere, I've decided to post to LKML, hoping that >> someone here can help me. >> >> First, I'll explain the background of my problem. My grief is the >> switchable GPU in my Lenovo Ideapad U330. The BIOS supports two >> options "Discrete only" (only the ATI card is visible on the BUS) and >> "Switchable" (both ATI and Intel card visible on the bus). The >> problem is the lack of a third option "Integrated", in which only the >> Intel card would be powered off. Lenovo refused to introduce such an >> option into the BIOS, stating that it's a feature request and not a >> bug. >> >> To save battery power I'd like to be able to run on the Intel card. >> However, with the "Switchable" option, powertop indicates huge power >> usage (24W), which can only be explained by the fact that both cards >> draw power. >> >> Thus, my question is the following: >> Is there a way to explicitly put a device into ACPI D0? I would like >> to do that to the ATI card on boot. >> >> I've tried the following code: >> http://ftp.chg.ru/pub/parallel/scyld/diag/pci-config.c >> But it didn't work (the ATI card was still on). > > Your best bet might be to load a driver for the ATI card that puts it > into PCI D3 state until used. There may be other ways to save power on > the disabled part as well... > > Alex, is this something you've looked at at all?
The xf86-video-ati ddx can turn off the displays and reduce the clocks and pcie lanes, but I haven't sorted out all the D3 stuff yet. As for the switchable graphics, you might find the page below useful. No idea if it will work or fry your hardware: http://ubuntuforums.org/showthread.php?p=7944950
Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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