Huang, please try this patch. BR, Jani.
On Tue, 29 Sep 2015, Jani Nikula <jani.nik...@intel.com> wrote: > Also adding Cc: intel-gfx, please include that in follow-ups. > > Thanks, > Jani. > > On Tue, 29 Sep 2015, Jani Nikula <jani.nik...@intel.com> wrote: >> Although we don't support or enable CPU PWM with LPT/SPT based systems, >> it may have been enabled prior to loading the driver. Disable the CPU >> PWM on LPT/SPT backlight disable to avoid warnings on LCPLL disable. >> >> The issue has been present on BDW since BDW enabling, but was recently >> introduced on HSW with >> >> commit 437b15b8017e0d946453c10794b0c5d4591cf180 >> Author: Jani Nikula <jani.nik...@intel.com> >> Date: Fri Sep 4 16:55:13 2015 +0300 >> >> drm/i915: use pch backlight override on hsw too >> >> Reference: http://mid.gmane.org/87y4frhwsn....@yhuang-dev.intel.com >> Reported-by: kernel test robot <ying.hu...@intel.com> >> Signed-off-by: Jani Nikula <jani.nik...@intel.com> >> --- >> drivers/gpu/drm/i915/intel_panel.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/drivers/gpu/drm/i915/intel_panel.c >> b/drivers/gpu/drm/i915/intel_panel.c >> index dd71e7f139e3..c9c94d05f3dd 100644 >> --- a/drivers/gpu/drm/i915/intel_panel.c >> +++ b/drivers/gpu/drm/i915/intel_panel.c >> @@ -731,6 +731,20 @@ static void lpt_disable_backlight(struct >> intel_connector *connector) >> >> intel_panel_actually_set_backlight(connector, 0); >> >> + /* >> + * Although we don't support or enable CPU PWM with LPT/SPT based >> + * systems, it may have been enabled prior to loading the >> + * driver. Disable to avoid warnings on LCPLL disable. >> + * >> + * This needs rework if we need to add support for CPU PWM on PCH split >> + * platforms. >> + */ >> + tmp = I915_READ(BLC_PWM_CPU_CTL2); >> + if (tmp & BLM_PWM_ENABLE) { >> + DRM_DEBUG_KMS("cpu backlight was enabled, disabling\n"); >> + I915_WRITE(BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE); >> + } >> + >> tmp = I915_READ(BLC_PWM_PCH_CTL1); >> I915_WRITE(BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE); >> } >> -- >> 2.1.4 >> > > -- > Jani Nikula, Intel Open Source Technology Center -- Jani Nikula, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
