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 :( -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
