On Mon, Nov 14, 2011 at 21:39, Eugeni Dodonov <eugeni.dodonov at intel.com> wrote: > Most of the rc6-related hangs and major issues were addressed for the past > months. > > Let's re-enable it by default to provide a more wider testing, and catch > the remaining problems. > > According to tests, enablement of rc6 results in up to +50% improvements > in power usage and battery life, so it certainly would be a nice feature > to have enabled by default. > > Also, most of the issues related to rc6 seem to came from VTd, so if you > are experiencing any problems with it, try disabling VTd in bios or using > intel_iommu=off kernel parameter to investigate whether it solves the > issue. > > Acked-by: Keith Packard <keithp at keithp.com> > CC: Daniel Vetter <daniel.vetter at ffwll.ch> > CC: Jesse Barnes <jbarnes at virtuousgeek.org> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38567 > Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com> Iirc the same applies to rc6 as to semaphores. We have bug reports that it causes hard-hangs in combination with DMAR. I haven't yet gotten around to poking the relevant reporters whether ppgtt changes anything, because internet access here at the Intel Poland site sucks. So again I think we need to disable this on snb when DMAR is on. -Daniel -- Daniel Vetter daniel.vetter at ffwll.ch - +41 (0) 79 365 57 48 - http://blog.ffwll.ch
