This is yet another chapter in the ongoing saga of bringing RC6 to Sandy Bridge machines by default. Now that we have discovered that RC6 issues are triggered by RC6+ state, let's try to disable it by default. Plain RC6 is the one responsible for most energy savings, and so far it haven't given any problems - at least, none we are aware of. So with this, when i915_enable_rc6=-1 (e.g., the default value), we'll attempt to enable plain RC6 only on SNB. For Ivy Bridge, the behavior stays the same as always - we enable both RC6 and deep RC6. Note that while this exact patch does not has explicit tested-by's, the equivalent settings were fixed in 3.3 kernel by a smaller patch. And it has also received considerable testing through Canonical RC6 task-force testing at https://wiki.ubuntu.com/Kernel/PowerManagementRC6. Up to date, it looks like all the known issues are gone. v2: improve description and reference a couple of open bugs related to RC6 which seem to be fixed with this change. References: https://bugs.freedesktop.org/show_bug.cgi?id=41682 References: https://bugs.freedesktop.org/show_bug.cgi?id=38567 References: https://bugs.freedesktop.org/show_bug.cgi?id=44867 Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com> --- drivers/gpu/drm/i915/intel_display.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index c6d8bc4..dcae2c9 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8233,11 +8233,11 @@ static int intel_enable_rc6(struct drm_device *dev) * Disable rc6 on Sandybridge */ if (INTEL_INFO(dev)->gen == 6) { - DRM_DEBUG_DRIVER("Sandybridge: RC6 disabled\n"); - return 0; + DRM_DEBUG_DRIVER("Sandybridge: deep RC6 disabled\n"); + return INTEL_RC6_ENABLE; } - DRM_DEBUG_DRIVER("RC6 enabled\n"); - return 1; + DRM_DEBUG_DRIVER("RC6 and deep RC6 enabled\n"); + return (INTEL_RC6_ENABLE | INTEL_RC6p_ENABLE); } void gen6_enable_rps(struct drm_i915_private *dev_priv) -- 1.7.9.4
