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 125000 instead of 50000 seems to fix the issue. The previous patch used 150000 but as it turns out this doesn't work everywhere. After getting such a machine, I bisected the highest value which works, which is 125000, so here it is. I also measured the idle power usage before/after this patch and didn't see a difference on a sandy bridge laptop. On haswell and up, it makes a big difference, so we want to keep it at 50k there. It also seems like haswell doesn't have the RC6 issues that sandy bridge has so the 50k value is fine. Signed-off-by: Stéphane Marchesin <marcheu@xxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_pm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 51a2a60..71839f8 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3250,7 +3250,10 @@ static void gen6_enable_rps(struct drm_device *dev) I915_WRITE(GEN6_RC_SLEEP, 0); I915_WRITE(GEN6_RC1e_THRESHOLD, 1000); - I915_WRITE(GEN6_RC6_THRESHOLD, 50000); + if (INTEL_INFO(dev)->gen <= 6 || IS_IVYBRIDGE(dev)) + I915_WRITE(GEN6_RC6_THRESHOLD, 125000); + else + I915_WRITE(GEN6_RC6_THRESHOLD, 50000); I915_WRITE(GEN6_RC6p_THRESHOLD, 150000); I915_WRITE(GEN6_RC6pp_THRESHOLD, 64000); /* unused */ -- 1.8.3 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
