On Fri, Jun 14, 2013 at 12:32 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > On Fri, Jun 14, 2013 at 9:13 PM, St?phane Marchesin > <marcheu at chromium.org> wrote: >> On Wed, Jun 12, 2013 at 2:41 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote: >>> On Tue, Jun 11, 2013 at 03:49:26PM -0700, St?phane Marchesin wrote: >>>> It's basically the same deal as the RC6+ issues on ivy bridge >>>> except this time with RC6 on sandy bridge. Like last time the >>>> core of the issue is that the timings don't work 100% with our >>>> voltage regulator. So from time to time, the kernel will print >>>> a warning message about the GPU not getting out of RC6. In >>>> particular, I found this fairly easy to reproduce during >>>> suspend/resume. >>>> >>>> Changing the threshold to 150000 instead of 50000 seems to fix >>>> the issue. >>>> >>>> I also measured the idle power usage before/after this patch and >>>> didn't see a difference on a sandy bridge laptop. >>>> >>>> Signed-off-by: St?phane Marchesin <marcheu at chromium.org> >>> >>> One magic number for another with no idea what is blowing up - I fear we >>> are just changing the frequency of the hang. I've pinged a number of snb >>> rc6 bug reports to see if we get a bite. >> >> Yup, if only Intel documented those registers :) > > We've spammed rc6 bugs in bugzilla, one reporter says that this patch > breaks rc6 from "sometimes it doesn't work after resume" to "always > broken": > > https://bugs.freedesktop.org/show_bug.cgi?id=54089#c63 > > So I guess I can't merge this :( Yeah I was actually going to send an email to withdraw this patch, as it prevents rc6 from working on some machines here. So I guess I found out the same thing. St?phane
