Messages in this thread | | | Date | Sat, 3 Dec 2011 09:19:29 +0100 | Subject | Re: i915: RC6 causes sudden shutdowns | From | Patrik Kullman <> |
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2011/12/2 Andrew Lutomirski <luto@mit.edu>: > On Thu, Dec 1, 2011 at 9:00 PM, Patrik Kullman <patrik.kullman@gmail.com> wrote: >> 2011/12/1 Andy Lutomirski <luto@mit.edu>: >>> On 11/23/2011 03:43 PM, Patrik Kullman wrote: >>>> Hi, >>>> >>>> I recently acquired the Asus Zenbook UX31E but have been looking for >>>> ways to extend the battery life. >>>> >>>> I read that the i915_enable_rc6 parameter could decrease power usage >>>> significantly and tried it with the 3.1.1 and 3.1.2 kernels, and >>>> indeed it does. >>>> However, I (and the other Zenbook-owners from the Ubuntu forums) >>>> experience sudden, unexpected shutdowns (for me, 1-4 times per day) >>>> with this parameter. >>>> It's as sudden as a power loss. >>> >>> Do you have DMAR enabled? If so, it's a known problem and it's being >>> worked on (and the default will not change for you AFAICT). If not, you >>> should send a bug report to the intel-gfx -- several people there care >>> about this. >>> >>> --Andy >> >> Well, it's not something I've explicitly enabled. >> >> Is it on by default? > > Depends on config options. You can probably get a good idea by > looking for "DMAR" in your kernel log. > >> >> If so, any reason why I wouldn't want to disable it? > > There are three reasons to enable it: > > 1. If you're paranoid and want to (partially) protect your system > against malicious PCI/PCIe cards. > 2. If you assign devices in your system to VM guests. > 3. If you have more than 4GB of RAM and you have DMA-capable devices > that can only address 32 bits, then you might get a performance boost. > > In other words, for normal desktop use, you don't need it. Try > booting with intel_iommu=off. > > --Andy
As reported by another Ubuntu Zenbook user (http://ubuntuforums.org/showpost.php?p=11507684&postcount=207):
Sadly i still get random shutdowns with 3.2-rc4. I have noticed that if i just leave my computer on, and does not use it (i have disabled the screensaver), the crashes does not accrue.
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash drm.debug=4 intel_iommu=off i915.modeset=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1 i915.i915_enable_rc6=1 pcie_aspm=force" -- 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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