Also adding Cc: intel-gfx, please include that in follow-ups. Thanks, Jani. On Tue, 29 Sep 2015, Jani Nikula <jani.nikula@xxxxxxxxx> 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.nikula@xxxxxxxxx> > Date: Fri Sep 4 16:55:13 2015 +0300 > > drm/i915: use pch backlight override on hsw too > > Reference: http://mid.gmane.org/87y4frhwsn.fsf@xxxxxxxxxxxxxxxxxxxx > Reported-by: kernel test robot <ying.huang@xxxxxxxxx> > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> > --- > 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 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
