Re: [Intel-gfx] [BUG] [REGRESSION] [BISECTED] -rc1 breaks audio over HDMI for i915

[Takashi Iwai]

On Tue, 23 Feb 2016 20:09:02 +0100,
Martin Kepplinger wrote:
> 
> Am 2016-02-23 um 18:14 schrieb Ville SyrjÃlÃ:
> > On Tue, Feb 23, 2016 at 05:57:40PM +0100, Takashi Iwai wrote:
> >> On Mon, 22 Feb 2016 22:37:28 +0100,
> >> Martin Kepplinger wrote:
> >>>
> >>> Am 2016-02-22 um 20:10 schrieb Takashi Iwai:
> >>>> On Mon, 22 Feb 2016 19:58:18 +0100,
> >>>> Martin Kepplinger wrote:
> >>>>>
> >>>>> Am 2016-02-22 um 15:12 schrieb Takashi Iwai:
> >>>>>> On Mon, 22 Feb 2016 15:02:56 +0100,
> >>>>>> Martin Kepplinger wrote:
> >>>>>>>> And how about my questions in the previous mail?  Does
> >>>>>>>> i915_audio_component_get_eld() is called and returns 0?
> >>>>>>>> And is monitor_present set true or false?
> >>>>>>>
> >>>>>>> i915_audio_component_get_eld() returns 0 and monitor_present is 0.
> >>>>>>>>
> >>>>>>>> If i915_audio_component_get_eld() is called but returns zero, track
> >>>>>>>> the code flow there.  It means either intel_encoder is NULL or
> >>>>>>>> intel_dig_port->audio_connector is NULL.
> >>>>>>>
> >>>>>>> intel_dig_port->audio_connector is NULL!
> >>>>>>>
> >>>>>>> (when called during boot and during HDMI plugin)
> >>>>>>
> >>>>>> Interesting.  The relevant code flow should be like:
> >>>>>>
> >>>>>>   intel_audio_codec_enable()
> >>>>>>   -> acomp->audio_ops->pin_eld_notify()
> >>>>>>     -> intel_pin_eld_notify()
> >>>>>>       -> check_presence_and_report()
> >>>>>>         -> hdmi_present_sense()
> >>>>>> 	  -> sync_eld_via_acomp()
> >>>>>> 	    -> snd_hdac_acomp_get_eld()
> >>>>>> 	      -> i915_audio_component_get_eld()
> >>>>>>
> >>>>>> So, at first, check whether intel_dig_port in both
> >>>>>> intel_audio_codec_enable() and i915_audio_component_get_eld() points
> >>>>>> to the same object address.  The audio_connector must be set in
> >>>>>> intel_audio_codec_enable(), thus basically it must be non-NULL at
> >>>>>> i915_audio_component_get_eld(), too.
> >>>>>>
> >>>>>
> >>>>> intel_dig_port is *not* the same object in these 2 places. During
> >>>>> plugin, see:
> >>>>>
> >>>>> [  146.934091] in intel_audio_codec_enable: intel_dig_port is
> >>>>> ffff8800a1f54000
> >>>>> [  146.934121] in i915_audio_component_get_eld: intel_dig_port is
> >>>>> ffff880244f7d000
> >>>>>
> >>>>> sorry for the slow responses. I'll try to go back that direction unless
> >>>>> again someone comes up with other suggestions.
> >>>>
> >>>> Thanks, this makes sense.  It implies that the digital port mapping is
> >>>> somehow wrong.  There are three places setting dig_port_map[], one in
> >>>> intel_ddi_init(), one in intel_dp_init() and another in
> >>>> intel_hdmi_init().  Try to check which function creates which object
> >>>> assigned to which port number, together with drm.debug=0x0e debug
> >>>> messages.
> >>>>
> >>> without using drm.debug=0x0e, but by printing the kmalloc'ed objects in
> >>> those 3 functions with ports, I found:
> >>>
> >>> 2 of them are running, only during boot:
> >>>
> >>> [    2.322865] intel_hdmi_init: intel_dig_port is ffff880242564000  port 1
> >>> [    2.322999] intel_dp_init: intel_dig_port is ffff880242f30000  port 1
> >>>
> >>> is is correct for them to have both port 1? Any more ideas?
> >>
> >> Adding intel-gfx ML to Cc.
> >>
> >> Martin, is the machine SandyBridge or IvyBridge?
> >>
> >> In anyway it's PCH_SPLIT and there can call both intel_hdmi_init() and 
> >> intel_dp_init() for the same port although both functions map
> >> intel_dig_port[].  The assumption of intel_dig_port[] reverse mapping
> >> is that there is only a single intel_dig_port assigned to a port, but
> >> this doesn't look correct...
> > 
> > On pre-HSW there can indeed be two encoders for the same port.
> > And I'm planning to change HSW+ to follow that model as well,
> > but I've been busy with other stuff to finish off that work [1]
> > 
> > [1] https://lists.freedesktop.org/archives/intel-gfx/2015-December/082384.html
> > 
> 
> So your work wouldn't fix hdmi-audio pre-HSW here?

The only question is how to pass intel_dig_port.  The current code is
a kind of optimization suggested after my initial patch.

Since dig_port_map[] is used only for the audio callback, we can
assign it dynamically just before the callbacks.

Could you try the patch below?  (It's totally untested.)

> Anyways, a quick fix would be good, and if not that, remember marking
> future changes that fix this, for stable.
> 
> What implications would something like the following, that Takashi
> suggested, have on other systems?

We'd take that action as a last resort, but it should be limited to
pre-HSW.  So if any, we'd need the check of codec ID.


thanks,

Takashi

---
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 31f6d212fb1b..e2bee6957cc0 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -521,6 +521,9 @@ void intel_audio_codec_enable(struct intel_encoder *intel_encoder)
 
 	connector->eld[6] = drm_av_sync_delay(connector, adjusted_mode) / 2;
 
+	/* referred in audio callbacks */
+	dev_priv->dig_port_map[port] = intel_encoder;
+
 	if (dev_priv->display.audio_codec_enable)
 		dev_priv->display.audio_codec_enable(connector, intel_encoder,
 						     adjusted_mode);
@@ -558,6 +561,8 @@ void intel_audio_codec_disable(struct intel_encoder *intel_encoder)
 
 	if (acomp && acomp->audio_ops && acomp->audio_ops->pin_eld_notify)
 		acomp->audio_ops->pin_eld_notify(acomp->audio_ops->audio_ptr, (int) port);
+
+	dev_priv->dig_port_map[port] = NULL;
 }
 
 /**
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index e6408e5583d7..63ba42aa2985 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -3311,7 +3311,6 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
 	intel_encoder->get_config = intel_ddi_get_config;
 
 	intel_dig_port->port = port;
-	dev_priv->dig_port_map[port] = intel_encoder;
 	intel_dig_port->saved_port_bits = I915_READ(DDI_BUF_CTL(port)) &
 					  (DDI_BUF_PORT_REVERSAL |
 					   DDI_A_4_LANES);
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 796e3d313cb9..ac6a37cbd323 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -6035,7 +6035,6 @@ intel_dp_init(struct drm_device *dev,
 	}
 
 	intel_dig_port->port = port;
-	dev_priv->dig_port_map[port] = intel_encoder;
 	intel_dig_port->dp.output_reg = output_reg;
 
 	intel_encoder->type = INTEL_OUTPUT_DISPLAYPORT;
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 4a77639a489d..23ee48dc765f 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -2146,7 +2146,6 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
 void intel_hdmi_init(struct drm_device *dev,
 		     i915_reg_t hdmi_reg, enum port port)
 {
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_digital_port *intel_dig_port;
 	struct intel_encoder *intel_encoder;
 	struct intel_connector *intel_connector;
@@ -2215,7 +2214,6 @@ void intel_hdmi_init(struct drm_device *dev,
 		intel_encoder->cloneable |= 1 << INTEL_OUTPUT_HDMI;
 
 	intel_dig_port->port = port;
-	dev_priv->dig_port_map[port] = intel_encoder;
 	intel_dig_port->hdmi.hdmi_reg = hdmi_reg;
 	intel_dig_port->dp.output_reg = INVALID_MMIO_REG;