diff mbox series

[2/7] drm/i915/sdvo: Implement proper HDMI audio support for SDVO

Message ID 20190409144054.24561-3-ville.syrjala@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915: Fix SDVO HDMI audio | expand

Commit Message

Ville Syrjälä April 9, 2019, 2:40 p.m. UTC 
From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Our SDVO audio support is pretty bogus. We can't push audio over the
SDVO bus, so trying to enable audio in the SDVO control register doesn't
do anything. In fact it looks like the SDVO encoder will always mix in
the audio coming over HDA, and there's no (at least documented) way to
disable that from our side. So HDMI audio does work currently but only by
luck really. What is missing though is the ELD.

To pass the ELD to the audio driver we need to write it to magic buffer
in the SDVO encoder hardware which then gets pulled out via HDA in the
other end. Ie. pretty much the same thing we had for native HDMI before
we started to just pass the ELD between the drivers. This sort of
explains why we even have that silly hardware buffer with native HDMI.

$ cat /proc/asound/card0/eld#1.0
-monitor_present		0
-eld_valid		0
+monitor_present		1
+eld_valid		1
+monitor_name		LG TV
+connection_type		HDMI
+...

This also fixes our state readout since we can now query the SDVO
encoder about the state of the "ELD valid" and "presence detect"
bits. As mentioned those don't actually control whether audio
gets sent over the HDMI cable, but it's the best we can do.

Cc: stable@vger.kernel.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: zardam@gmail.com
Tested-by: zardam@gmail.com
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108976
Fixes: de44e256b92c ("drm/i915/sdvo: Shut up state checker with hdmi cards on gen3")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_sdvo.c      | 58 +++++++++++++++++++++-----
 drivers/gpu/drm/i915/intel_sdvo_regs.h |  3 ++
 2 files changed, 50 insertions(+), 11 deletions(-)

Comments

Ville Syrjälä April 9, 2019, 8 p.m. UTC | #1 
On Tue, Apr 09, 2019 at 05:40:49PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Our SDVO audio support is pretty bogus. We can't push audio over the
> SDVO bus, so trying to enable audio in the SDVO control register doesn't
> do anything. In fact it looks like the SDVO encoder will always mix in
> the audio coming over HDA, and there's no (at least documented) way to
> disable that from our side. So HDMI audio does work currently but only by
> luck really. What is missing though is the ELD.

Hmm. Looks like I forgot to update this text after the gen3 bug was
reported. The situation is that audio works on gen4 by luck. On gen3
it got broken by the referenced commit since we no longer enable
HDMI encoding on the SDVO device (that will stop audio transmission
entirely).

> 
> To pass the ELD to the audio driver we need to write it to magic buffer
> in the SDVO encoder hardware which then gets pulled out via HDA in the
> other end. Ie. pretty much the same thing we had for native HDMI before
> we started to just pass the ELD between the drivers. This sort of
> explains why we even have that silly hardware buffer with native HDMI.
> 
> $ cat /proc/asound/card0/eld#1.0
> -monitor_present		0
> -eld_valid		0
> +monitor_present		1
> +eld_valid		1
> +monitor_name		LG TV
> +connection_type		HDMI
> +...
> 
> This also fixes our state readout since we can now query the SDVO
> encoder about the state of the "ELD valid" and "presence detect"
> bits. As mentioned those don't actually control whether audio
> gets sent over the HDMI cable, but it's the best we can do.
> 
> Cc: stable@vger.kernel.org
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: zardam@gmail.com
> Tested-by: zardam@gmail.com
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108976
> Fixes: de44e256b92c ("drm/i915/sdvo: Shut up state checker with hdmi cards on gen3")
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_sdvo.c      | 58 +++++++++++++++++++++-----
>  drivers/gpu/drm/i915/intel_sdvo_regs.h |  3 ++
>  2 files changed, 50 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> index 61db07244296..7f64352a3413 100644
> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> @@ -916,6 +916,13 @@ static bool intel_sdvo_set_colorimetry(struct intel_sdvo *intel_sdvo,
>  	return intel_sdvo_set_value(intel_sdvo, SDVO_CMD_SET_COLORIMETRY, &mode, 1);
>  }
>  
> +static bool intel_sdvo_set_audio_state(struct intel_sdvo *intel_sdvo,
> +				       u8 audio_state)
> +{
> +	return intel_sdvo_set_value(intel_sdvo, SDVO_CMD_SET_AUDIO_STAT,
> +				    &audio_state, 1);
> +}
> +
>  #if 0
>  static void intel_sdvo_dump_hdmi_buf(struct intel_sdvo *intel_sdvo)
>  {
> @@ -1487,11 +1494,6 @@ static void intel_sdvo_pre_enable(struct intel_encoder *intel_encoder,
>  	else
>  		sdvox |= SDVO_PIPE_SEL(crtc->pipe);
>  
> -	if (crtc_state->has_audio) {
> -		WARN_ON_ONCE(INTEL_GEN(dev_priv) < 4);
> -		sdvox |= SDVO_AUDIO_ENABLE;
> -	}
> -
>  	if (INTEL_GEN(dev_priv) >= 4) {
>  		/* done in crtc_mode_set as the dpll_md reg must be written early */
>  	} else if (IS_I945G(dev_priv) || IS_I945GM(dev_priv) ||
> @@ -1635,8 +1637,13 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder,
>  	if (sdvox & HDMI_COLOR_RANGE_16_235)
>  		pipe_config->limited_color_range = true;
>  
> -	if (sdvox & SDVO_AUDIO_ENABLE)
> -		pipe_config->has_audio = true;
> +	if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_AUDIO_STAT,
> +				 &val, 1)) {
> +		u8 mask = SDVO_AUDIO_ELD_VALID | SDVO_AUDIO_PRESENCE_DETECT;
> +
> +		if ((val & mask) == mask)
> +			pipe_config->has_audio = true;
> +	}
>  
>  	if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_ENCODE,
>  				 &val, 1)) {
> @@ -1647,6 +1654,32 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder,
>  	intel_sdvo_get_avi_infoframe(intel_sdvo, pipe_config);
>  }
>  
> +static void intel_sdvo_disable_audio(struct intel_sdvo *intel_sdvo)
> +{
> +	intel_sdvo_set_audio_state(intel_sdvo, 0);
> +}
> +
> +static void intel_sdvo_enable_audio(struct intel_sdvo *intel_sdvo,
> +				    const struct intel_crtc_state *crtc_state,
> +				    const struct drm_connector_state *conn_state)
> +{
> +	const struct drm_display_mode *adjusted_mode =
> +		&crtc_state->base.adjusted_mode;
> +	struct drm_connector *connector = conn_state->connector;
> +	u8 *eld = connector->eld;
> +
> +	eld[6] = drm_av_sync_delay(connector, adjusted_mode) / 2;
> +
> +	intel_sdvo_set_audio_state(intel_sdvo, 0);
> +
> +	intel_sdvo_write_infoframe(intel_sdvo, SDVO_HBUF_INDEX_ELD,
> +				   SDVO_HBUF_TX_DISABLED,
> +				   eld, drm_eld_size(eld));
> +
> +	intel_sdvo_set_audio_state(intel_sdvo, SDVO_AUDIO_ELD_VALID |
> +				   SDVO_AUDIO_PRESENCE_DETECT);
> +}
> +
>  static void intel_disable_sdvo(struct intel_encoder *encoder,
>  			       const struct intel_crtc_state *old_crtc_state,
>  			       const struct drm_connector_state *conn_state)
> @@ -1656,6 +1689,9 @@ static void intel_disable_sdvo(struct intel_encoder *encoder,
>  	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->base.crtc);
>  	u32 temp;
>  
> +	if (old_crtc_state->has_audio)
> +		intel_sdvo_disable_audio(intel_sdvo);
> +
>  	intel_sdvo_set_active_outputs(intel_sdvo, 0);
>  	if (0)
>  		intel_sdvo_set_encoder_power_state(intel_sdvo,
> @@ -1741,6 +1777,9 @@ static void intel_enable_sdvo(struct intel_encoder *encoder,
>  		intel_sdvo_set_encoder_power_state(intel_sdvo,
>  						   DRM_MODE_DPMS_ON);
>  	intel_sdvo_set_active_outputs(intel_sdvo, intel_sdvo->attached_output);
> +
> +	if (pipe_config->has_audio)
> +		intel_sdvo_enable_audio(intel_sdvo, pipe_config, conn_state);
>  }
>  
>  static enum drm_mode_status
> @@ -2603,7 +2642,6 @@ static bool
>  intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
>  {
>  	struct drm_encoder *encoder = &intel_sdvo->base.base;
> -	struct drm_i915_private *dev_priv = to_i915(encoder->dev);
>  	struct drm_connector *connector;
>  	struct intel_encoder *intel_encoder = to_intel_encoder(encoder);
>  	struct intel_connector *intel_connector;
> @@ -2640,9 +2678,7 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
>  	encoder->encoder_type = DRM_MODE_ENCODER_TMDS;
>  	connector->connector_type = DRM_MODE_CONNECTOR_DVID;
>  
> -	/* gen3 doesn't do the hdmi bits in the SDVO register */
> -	if (INTEL_GEN(dev_priv) >= 4 &&
> -	    intel_sdvo_is_hdmi_connector(intel_sdvo, device)) {
> +	if (intel_sdvo_is_hdmi_connector(intel_sdvo, device)) {
>  		connector->connector_type = DRM_MODE_CONNECTOR_HDMIA;
>  		intel_sdvo_connector->is_hdmi = true;
>  	}
> diff --git a/drivers/gpu/drm/i915/intel_sdvo_regs.h b/drivers/gpu/drm/i915/intel_sdvo_regs.h
> index db0ed499268a..e9ba3b047f93 100644
> --- a/drivers/gpu/drm/i915/intel_sdvo_regs.h
> +++ b/drivers/gpu/drm/i915/intel_sdvo_regs.h
> @@ -707,6 +707,9 @@ struct intel_sdvo_enhancements_arg {
>  #define SDVO_CMD_GET_AUDIO_ENCRYPT_PREFER 0x90
>  #define SDVO_CMD_SET_AUDIO_STAT		0x91
>  #define SDVO_CMD_GET_AUDIO_STAT		0x92
> +  #define SDVO_AUDIO_ELD_VALID		(1 << 0)
> +  #define SDVO_AUDIO_PRESENCE_DETECT	(1 << 1)
> +  #define SDVO_AUDIO_CP_READY		(1 << 2)
>  #define SDVO_CMD_SET_HBUF_INDEX		0x93
>    #define SDVO_HBUF_INDEX_ELD		0
>    #define SDVO_HBUF_INDEX_AVI_IF	1
> -- 
> 2.21.0
Imre Deak June 6, 2019, 2:43 p.m. UTC | #2 
On Tue, Apr 09, 2019 at 11:00:10PM +0300, Ville Syrjälä wrote:
> On Tue, Apr 09, 2019 at 05:40:49PM +0300, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Our SDVO audio support is pretty bogus. We can't push audio over the
> > SDVO bus, so trying to enable audio in the SDVO control register doesn't
> > do anything. In fact it looks like the SDVO encoder will always mix in
> > the audio coming over HDA, and there's no (at least documented) way to
> > disable that from our side. So HDMI audio does work currently but only by
> > luck really. What is missing though is the ELD.
> 
> Hmm. Looks like I forgot to update this text after the gen3 bug was
> reported. The situation is that audio works on gen4 by luck. On gen3
> it got broken by the referenced commit since we no longer enable
> HDMI encoding on the SDVO device (that will stop audio transmission
> entirely).
> 
> > 
> > To pass the ELD to the audio driver we need to write it to magic buffer
> > in the SDVO encoder hardware which then gets pulled out via HDA in the
> > other end. Ie. pretty much the same thing we had for native HDMI before
> > we started to just pass the ELD between the drivers. This sort of
> > explains why we even have that silly hardware buffer with native HDMI.
> > 
> > $ cat /proc/asound/card0/eld#1.0
> > -monitor_present		0
> > -eld_valid		0
> > +monitor_present		1
> > +eld_valid		1
> > +monitor_name		LG TV
> > +connection_type		HDMI
> > +...
> > 
> > This also fixes our state readout since we can now query the SDVO
> > encoder about the state of the "ELD valid" and "presence detect"
> > bits. As mentioned those don't actually control whether audio
> > gets sent over the HDMI cable, but it's the best we can do.
> > 
> > Cc: stable@vger.kernel.org
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: zardam@gmail.com
> > Tested-by: zardam@gmail.com
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108976
> > Fixes: de44e256b92c ("drm/i915/sdvo: Shut up state checker with hdmi cards on gen3")
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Matches the sdvo specs and bspec (SDVO_AUDIO_ENABLE is a reserved/MBZ
bit on GEN3,3.5, and on GEN4 it's probably HDMI specific, since there is
no audio traffic over the SDVO bus):

Reviewed-by: Imre Deak <imre.deak@intel.com>

Btw, is it guaranteed that we have a valid ELD when
force_audio == HDMI_AUDIO_ON ?

> > ---
> >  drivers/gpu/drm/i915/intel_sdvo.c      | 58 +++++++++++++++++++++-----
> >  drivers/gpu/drm/i915/intel_sdvo_regs.h |  3 ++
> >  2 files changed, 50 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> > index 61db07244296..7f64352a3413 100644
> > --- a/drivers/gpu/drm/i915/intel_sdvo.c
> > +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> > @@ -916,6 +916,13 @@ static bool intel_sdvo_set_colorimetry(struct intel_sdvo *intel_sdvo,
> >  	return intel_sdvo_set_value(intel_sdvo, SDVO_CMD_SET_COLORIMETRY, &mode, 1);
> >  }
> >  
> > +static bool intel_sdvo_set_audio_state(struct intel_sdvo *intel_sdvo,
> > +				       u8 audio_state)
> > +{
> > +	return intel_sdvo_set_value(intel_sdvo, SDVO_CMD_SET_AUDIO_STAT,
> > +				    &audio_state, 1);
> > +}
> > +
> >  #if 0
> >  static void intel_sdvo_dump_hdmi_buf(struct intel_sdvo *intel_sdvo)
> >  {
> > @@ -1487,11 +1494,6 @@ static void intel_sdvo_pre_enable(struct intel_encoder *intel_encoder,
> >  	else
> >  		sdvox |= SDVO_PIPE_SEL(crtc->pipe);
> >  
> > -	if (crtc_state->has_audio) {
> > -		WARN_ON_ONCE(INTEL_GEN(dev_priv) < 4);
> > -		sdvox |= SDVO_AUDIO_ENABLE;
> > -	}
> > -
> >  	if (INTEL_GEN(dev_priv) >= 4) {
> >  		/* done in crtc_mode_set as the dpll_md reg must be written early */
> >  	} else if (IS_I945G(dev_priv) || IS_I945GM(dev_priv) ||
> > @@ -1635,8 +1637,13 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder,
> >  	if (sdvox & HDMI_COLOR_RANGE_16_235)
> >  		pipe_config->limited_color_range = true;
> >  
> > -	if (sdvox & SDVO_AUDIO_ENABLE)
> > -		pipe_config->has_audio = true;
> > +	if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_AUDIO_STAT,
> > +				 &val, 1)) {
> > +		u8 mask = SDVO_AUDIO_ELD_VALID | SDVO_AUDIO_PRESENCE_DETECT;
> > +
> > +		if ((val & mask) == mask)
> > +			pipe_config->has_audio = true;
> > +	}
> >  
> >  	if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_ENCODE,
> >  				 &val, 1)) {
> > @@ -1647,6 +1654,32 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder,
> >  	intel_sdvo_get_avi_infoframe(intel_sdvo, pipe_config);
> >  }
> >  
> > +static void intel_sdvo_disable_audio(struct intel_sdvo *intel_sdvo)
> > +{
> > +	intel_sdvo_set_audio_state(intel_sdvo, 0);
> > +}
> > +
> > +static void intel_sdvo_enable_audio(struct intel_sdvo *intel_sdvo,
> > +				    const struct intel_crtc_state *crtc_state,
> > +				    const struct drm_connector_state *conn_state)
> > +{
> > +	const struct drm_display_mode *adjusted_mode =
> > +		&crtc_state->base.adjusted_mode;
> > +	struct drm_connector *connector = conn_state->connector;
> > +	u8 *eld = connector->eld;
> > +
> > +	eld[6] = drm_av_sync_delay(connector, adjusted_mode) / 2;
> > +
> > +	intel_sdvo_set_audio_state(intel_sdvo, 0);
> > +
> > +	intel_sdvo_write_infoframe(intel_sdvo, SDVO_HBUF_INDEX_ELD,
> > +				   SDVO_HBUF_TX_DISABLED,
> > +				   eld, drm_eld_size(eld));
> > +
> > +	intel_sdvo_set_audio_state(intel_sdvo, SDVO_AUDIO_ELD_VALID |
> > +				   SDVO_AUDIO_PRESENCE_DETECT);
> > +}
> > +
> >  static void intel_disable_sdvo(struct intel_encoder *encoder,
> >  			       const struct intel_crtc_state *old_crtc_state,
> >  			       const struct drm_connector_state *conn_state)
> > @@ -1656,6 +1689,9 @@ static void intel_disable_sdvo(struct intel_encoder *encoder,
> >  	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->base.crtc);
> >  	u32 temp;
> >  
> > +	if (old_crtc_state->has_audio)
> > +		intel_sdvo_disable_audio(intel_sdvo);
> > +
> >  	intel_sdvo_set_active_outputs(intel_sdvo, 0);
> >  	if (0)
> >  		intel_sdvo_set_encoder_power_state(intel_sdvo,
> > @@ -1741,6 +1777,9 @@ static void intel_enable_sdvo(struct intel_encoder *encoder,
> >  		intel_sdvo_set_encoder_power_state(intel_sdvo,
> >  						   DRM_MODE_DPMS_ON);
> >  	intel_sdvo_set_active_outputs(intel_sdvo, intel_sdvo->attached_output);
> > +
> > +	if (pipe_config->has_audio)
> > +		intel_sdvo_enable_audio(intel_sdvo, pipe_config, conn_state);
> >  }
> >  
> >  static enum drm_mode_status
> > @@ -2603,7 +2642,6 @@ static bool
> >  intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
> >  {
> >  	struct drm_encoder *encoder = &intel_sdvo->base.base;
> > -	struct drm_i915_private *dev_priv = to_i915(encoder->dev);
> >  	struct drm_connector *connector;
> >  	struct intel_encoder *intel_encoder = to_intel_encoder(encoder);
> >  	struct intel_connector *intel_connector;
> > @@ -2640,9 +2678,7 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
> >  	encoder->encoder_type = DRM_MODE_ENCODER_TMDS;
> >  	connector->connector_type = DRM_MODE_CONNECTOR_DVID;
> >  
> > -	/* gen3 doesn't do the hdmi bits in the SDVO register */
> > -	if (INTEL_GEN(dev_priv) >= 4 &&
> > -	    intel_sdvo_is_hdmi_connector(intel_sdvo, device)) {
> > +	if (intel_sdvo_is_hdmi_connector(intel_sdvo, device)) {
> >  		connector->connector_type = DRM_MODE_CONNECTOR_HDMIA;
> >  		intel_sdvo_connector->is_hdmi = true;
> >  	}
> > diff --git a/drivers/gpu/drm/i915/intel_sdvo_regs.h b/drivers/gpu/drm/i915/intel_sdvo_regs.h
> > index db0ed499268a..e9ba3b047f93 100644
> > --- a/drivers/gpu/drm/i915/intel_sdvo_regs.h
> > +++ b/drivers/gpu/drm/i915/intel_sdvo_regs.h
> > @@ -707,6 +707,9 @@ struct intel_sdvo_enhancements_arg {
> >  #define SDVO_CMD_GET_AUDIO_ENCRYPT_PREFER 0x90
> >  #define SDVO_CMD_SET_AUDIO_STAT		0x91
> >  #define SDVO_CMD_GET_AUDIO_STAT		0x92
> > +  #define SDVO_AUDIO_ELD_VALID		(1 << 0)
> > +  #define SDVO_AUDIO_PRESENCE_DETECT	(1 << 1)
> > +  #define SDVO_AUDIO_CP_READY		(1 << 2)
> >  #define SDVO_CMD_SET_HBUF_INDEX		0x93
> >    #define SDVO_HBUF_INDEX_ELD		0
> >    #define SDVO_HBUF_INDEX_AVI_IF	1
> > -- 
> > 2.21.0
> 
> -- 
> Ville Syrjälä
> Intel
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 61db07244296..7f64352a3413 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -916,6 +916,13 @@  static bool intel_sdvo_set_colorimetry(struct intel_sdvo *intel_sdvo,
 	return intel_sdvo_set_value(intel_sdvo, SDVO_CMD_SET_COLORIMETRY, &mode, 1);
 }
 
+static bool intel_sdvo_set_audio_state(struct intel_sdvo *intel_sdvo,
+				       u8 audio_state)
+{
+	return intel_sdvo_set_value(intel_sdvo, SDVO_CMD_SET_AUDIO_STAT,
+				    &audio_state, 1);
+}
+
 #if 0
 static void intel_sdvo_dump_hdmi_buf(struct intel_sdvo *intel_sdvo)
 {
@@ -1487,11 +1494,6 @@  static void intel_sdvo_pre_enable(struct intel_encoder *intel_encoder,
 	else
 		sdvox |= SDVO_PIPE_SEL(crtc->pipe);
 
-	if (crtc_state->has_audio) {
-		WARN_ON_ONCE(INTEL_GEN(dev_priv) < 4);
-		sdvox |= SDVO_AUDIO_ENABLE;
-	}
-
 	if (INTEL_GEN(dev_priv) >= 4) {
 		/* done in crtc_mode_set as the dpll_md reg must be written early */
 	} else if (IS_I945G(dev_priv) || IS_I945GM(dev_priv) ||
@@ -1635,8 +1637,13 @@  static void intel_sdvo_get_config(struct intel_encoder *encoder,
 	if (sdvox & HDMI_COLOR_RANGE_16_235)
 		pipe_config->limited_color_range = true;
 
-	if (sdvox & SDVO_AUDIO_ENABLE)
-		pipe_config->has_audio = true;
+	if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_AUDIO_STAT,
+				 &val, 1)) {
+		u8 mask = SDVO_AUDIO_ELD_VALID | SDVO_AUDIO_PRESENCE_DETECT;
+
+		if ((val & mask) == mask)
+			pipe_config->has_audio = true;
+	}
 
 	if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_ENCODE,
 				 &val, 1)) {
@@ -1647,6 +1654,32 @@  static void intel_sdvo_get_config(struct intel_encoder *encoder,
 	intel_sdvo_get_avi_infoframe(intel_sdvo, pipe_config);
 }
 
+static void intel_sdvo_disable_audio(struct intel_sdvo *intel_sdvo)
+{
+	intel_sdvo_set_audio_state(intel_sdvo, 0);
+}
+
+static void intel_sdvo_enable_audio(struct intel_sdvo *intel_sdvo,
+				    const struct intel_crtc_state *crtc_state,
+				    const struct drm_connector_state *conn_state)
+{
+	const struct drm_display_mode *adjusted_mode =
+		&crtc_state->base.adjusted_mode;
+	struct drm_connector *connector = conn_state->connector;
+	u8 *eld = connector->eld;
+
+	eld[6] = drm_av_sync_delay(connector, adjusted_mode) / 2;
+
+	intel_sdvo_set_audio_state(intel_sdvo, 0);
+
+	intel_sdvo_write_infoframe(intel_sdvo, SDVO_HBUF_INDEX_ELD,
+				   SDVO_HBUF_TX_DISABLED,
+				   eld, drm_eld_size(eld));
+
+	intel_sdvo_set_audio_state(intel_sdvo, SDVO_AUDIO_ELD_VALID |
+				   SDVO_AUDIO_PRESENCE_DETECT);
+}
+
 static void intel_disable_sdvo(struct intel_encoder *encoder,
 			       const struct intel_crtc_state *old_crtc_state,
 			       const struct drm_connector_state *conn_state)
@@ -1656,6 +1689,9 @@  static void intel_disable_sdvo(struct intel_encoder *encoder,
 	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->base.crtc);
 	u32 temp;
 
+	if (old_crtc_state->has_audio)
+		intel_sdvo_disable_audio(intel_sdvo);
+
 	intel_sdvo_set_active_outputs(intel_sdvo, 0);
 	if (0)
 		intel_sdvo_set_encoder_power_state(intel_sdvo,
@@ -1741,6 +1777,9 @@  static void intel_enable_sdvo(struct intel_encoder *encoder,
 		intel_sdvo_set_encoder_power_state(intel_sdvo,
 						   DRM_MODE_DPMS_ON);
 	intel_sdvo_set_active_outputs(intel_sdvo, intel_sdvo->attached_output);
+
+	if (pipe_config->has_audio)
+		intel_sdvo_enable_audio(intel_sdvo, pipe_config, conn_state);
 }
 
 static enum drm_mode_status
@@ -2603,7 +2642,6 @@  static bool
 intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
 {
 	struct drm_encoder *encoder = &intel_sdvo->base.base;
-	struct drm_i915_private *dev_priv = to_i915(encoder->dev);
 	struct drm_connector *connector;
 	struct intel_encoder *intel_encoder = to_intel_encoder(encoder);
 	struct intel_connector *intel_connector;
@@ -2640,9 +2678,7 @@  intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
 	encoder->encoder_type = DRM_MODE_ENCODER_TMDS;
 	connector->connector_type = DRM_MODE_CONNECTOR_DVID;
 
-	/* gen3 doesn't do the hdmi bits in the SDVO register */
-	if (INTEL_GEN(dev_priv) >= 4 &&
-	    intel_sdvo_is_hdmi_connector(intel_sdvo, device)) {
+	if (intel_sdvo_is_hdmi_connector(intel_sdvo, device)) {
 		connector->connector_type = DRM_MODE_CONNECTOR_HDMIA;
 		intel_sdvo_connector->is_hdmi = true;
 	}
diff --git a/drivers/gpu/drm/i915/intel_sdvo_regs.h b/drivers/gpu/drm/i915/intel_sdvo_regs.h
index db0ed499268a..e9ba3b047f93 100644
--- a/drivers/gpu/drm/i915/intel_sdvo_regs.h
+++ b/drivers/gpu/drm/i915/intel_sdvo_regs.h
@@ -707,6 +707,9 @@  struct intel_sdvo_enhancements_arg {
 #define SDVO_CMD_GET_AUDIO_ENCRYPT_PREFER 0x90
 #define SDVO_CMD_SET_AUDIO_STAT		0x91
 #define SDVO_CMD_GET_AUDIO_STAT		0x92
+  #define SDVO_AUDIO_ELD_VALID		(1 << 0)
+  #define SDVO_AUDIO_PRESENCE_DETECT	(1 << 1)
+  #define SDVO_AUDIO_CP_READY		(1 << 2)
 #define SDVO_CMD_SET_HBUF_INDEX		0x93
   #define SDVO_HBUF_INDEX_ELD		0
   #define SDVO_HBUF_INDEX_AVI_IF	1