Re: [PATCH 01/15] drm/i915: only disable DDI sound if intel_crtc->eld_vld

From: Daniel Vetter <daniel@ffwll.ch>
To: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: "Runyan, Arthur J" <arthur.j.runyan@intel.com>,
	intel-gfx@lists.freedesktop.org,
	Paulo Zanoni <paulo.r.zanoni@intel.com>
Subject: Re: [PATCH 01/15] drm/i915: only disable DDI sound if intel_crtc->eld_vld
Date: Sun, 17 Mar 2013 21:23:44 +0100	[thread overview]
Message-ID: <20130317202344.GJ9021@phenom.ffwll.local> (raw)
In-Reply-To: <20130307093123.GQ4469@intel.com>

On Thu, Mar 07, 2013 at 11:31:23AM +0200, Ville Syrjälä wrote:
> On Wed, Mar 06, 2013 at 08:03:08PM -0300, Paulo Zanoni wrote:
> > From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > 
> > We already have the same check on intel_enable_ddi. This patch
> > prevents "unclaimed register" messages when the power well is
> > disabled.
> > 
> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c |    9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index 56bb7cb..cd2f519 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -1347,9 +1347,12 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder)
> >  		ironlake_edp_backlight_off(intel_dp);
> >  	}
> >  
> > -	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
> > -	tmp &= ~((AUDIO_OUTPUT_ENABLE_A | AUDIO_ELD_VALID_A) << (pipe * 4));
> > -	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);
> > +	if (intel_crtc->eld_vld) {
> > +		tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
> > +		tmp &= ~((AUDIO_OUTPUT_ENABLE_A | AUDIO_ELD_VALID_A) <<
> > +			 (pipe * 4));
> > +		I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);
> > +	}
> 
> We set eld_vld=false before disabling the crtc in intel_crtc_disable().
> I think you need to rearrange that so that we clear eld_vld only
> after ->crtc_disable has been called.

I've forgotten to drop my bikeshed on the patch itself:

This looks a bit fishy since currently we assume that disabling something
just works (especially clearing a few registers). And I don't really
understand how we can hit unclaimed register issues since the pipe should
be enabled when we call this function here ...

So either transcoder eDP doesn't have audio, in which case I think it'd be
better to check for that here (plus ensure that we yell at callers for
integrated eDP in e.g. hsw_write_eld). Or it _does_ have audio, but the
audio stuff is in the power well. In which case we need to add a check.

Yes, I'm too lazy to check the docs myself, but tbh it's still w/e here so
don't want to fire up the work machine ;-)

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