Re: [Intel-gfx] [PATCH 09/22] drm/i915/audio: Read ELD buffer size from hardware

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 12 Oct 2022, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Tue, 11 Oct 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
>> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>
>> We currently read the ELD buffer size from hardware on g4x,
>> but on ilk+ we just hardcode it to 84 bytes. Let's unify
>> this and just do the hardware readout on all platforms,
>> in case the size changes in the future or something.
>>
>> TODO: should perhaps do the readout during driver init and
>> stash the results somewhere so that we could check that the
>> connector's ELD actually fits and not even try to enable audio
>> in that case...
>>
>> Cc: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
>> Cc: Kai Vehmanen <kai.vehmanen@linux.intel.com>
>> Cc: Takashi Iwai <tiwai@suse.de>
>> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>

Might add comments above the *_eld_buffer_size() functions to indicate
they return the buffer size in dwords, not bytes which would be the
obvious thing.

>
>> ---
>>  drivers/gpu/drm/i915/display/intel_audio.c | 49 ++++++++++++++++++----
>>  1 file changed, 42 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_audio.c b/drivers/gpu/drm/i915/display/intel_audio.c
>> index 3f328913fc90..abca5f23673a 100644
>> --- a/drivers/gpu/drm/i915/display/intel_audio.c
>> +++ b/drivers/gpu/drm/i915/display/intel_audio.c
>> @@ -304,6 +304,15 @@ static int audio_config_hdmi_get_n(const struct intel_crtc_state *crtc_state,
>>  	return 0;
>>  }
>>  
>> +static int g4x_eld_buffer_size(struct drm_i915_private *i915)
>> +{
>> +	u32 tmp;
>> +
>> +	tmp = intel_de_read(i915, G4X_AUD_CNTL_ST);
>> +
>> +	return REG_FIELD_GET(G4X_ELD_BUFFER_SIZE_MASK, tmp);
>> +}
>> +
>>  static void g4x_audio_codec_disable(struct intel_encoder *encoder,
>>  				    const struct intel_crtc_state *old_crtc_state,
>>  				    const struct drm_connector_state *old_conn_state)
>> @@ -329,10 +338,11 @@ static void g4x_audio_codec_enable(struct intel_encoder *encoder,
>>  
>>  	tmp = intel_de_read(i915, G4X_AUD_CNTL_ST);
>>  	tmp &= ~(G4X_ELD_VALID | G4X_ELD_ADDRESS_MASK);
>> -	len = REG_FIELD_GET(G4X_ELD_BUFFER_SIZE_MASK, tmp);
>>  	intel_de_write(i915, G4X_AUD_CNTL_ST, tmp);
>>  
>> +	len = g4x_eld_buffer_size(i915);
>>  	len = min(drm_eld_size(eld) / 4, len);
>> +
>>  	for (i = 0; i < len; i++)
>>  		intel_de_write(i915, G4X_HDMIW_HDMIEDID,
>>  			       *((const u32 *)eld + i));
>> @@ -442,6 +452,16 @@ hsw_audio_config_update(struct intel_encoder *encoder,
>>  		hsw_hdmi_audio_config_update(encoder, crtc_state);
>>  }
>>  
>> +static int hsw_eld_buffer_size(struct drm_i915_private *i915,
>> +			       enum transcoder cpu_transcoder)
>> +{
>> +	u32 tmp;
>> +
>> +	tmp = intel_de_read(i915, HSW_AUD_DIP_ELD_CTRL(cpu_transcoder));
>> +
>> +	return REG_FIELD_GET(IBX_ELD_BUFFER_SIZE_MASK, tmp);
>> +}
>> +
>>  static void hsw_audio_codec_disable(struct intel_encoder *encoder,
>>  				    const struct intel_crtc_state *old_crtc_state,
>>  				    const struct drm_connector_state *old_conn_state)
>> @@ -615,9 +635,10 @@ static void hsw_audio_codec_enable(struct intel_encoder *encoder,
>>  	tmp &= ~IBX_ELD_ADDRESS_MASK;
>>  	intel_de_write(i915, HSW_AUD_DIP_ELD_CTRL(cpu_transcoder), tmp);
>>  
>> -	/* Up to 84 bytes of hw ELD buffer */
>> -	len = min(drm_eld_size(eld), 84);
>> -	for (i = 0; i < len / 4; i++)
>> +	len = hsw_eld_buffer_size(i915, cpu_transcoder);
>> +	len = min(drm_eld_size(eld) / 4, len);
>> +
>> +	for (i = 0; i < len; i++)
>>  		intel_de_write(i915, HSW_AUD_EDID_DATA(cpu_transcoder),
>>  			       *((const u32 *)eld + i));
>>  
>> @@ -658,6 +679,19 @@ static void ilk_audio_regs_init(struct drm_i915_private *i915,
>>  	}
>>  }
>>  
>> +static int ilk_eld_buffer_size(struct drm_i915_private *i915,
>> +			       enum pipe pipe)
>> +{
>> +	struct ilk_audio_regs regs;
>> +	u32 tmp;
>> +
>> +	ilk_audio_regs_init(i915, pipe, &regs);
>> +
>> +	tmp = intel_de_read(i915, regs.aud_cntl_st);
>> +
>> +	return REG_FIELD_GET(IBX_ELD_BUFFER_SIZE_MASK, tmp);
>> +}
>> +
>>  static void ilk_audio_codec_disable(struct intel_encoder *encoder,
>>  				    const struct intel_crtc_state *old_crtc_state,
>>  				    const struct drm_connector_state *old_conn_state)
>> @@ -732,9 +766,10 @@ static void ilk_audio_codec_enable(struct intel_encoder *encoder,
>>  	tmp &= ~IBX_ELD_ADDRESS_MASK;
>>  	intel_de_write(i915, regs.aud_cntl_st, tmp);
>>  
>> -	/* Up to 84 bytes of hw ELD buffer */
>> -	len = min(drm_eld_size(eld), 84);
>> -	for (i = 0; i < len / 4; i++)
>> +	len = ilk_eld_buffer_size(i915, pipe);
>> +	len = min(drm_eld_size(eld) / 4, len);
>> +
>> +	for (i = 0; i < len; i++)
>>  		intel_de_write(i915, regs.hdmiw_hdmiedid,
>>  			       *((const u32 *)eld + i));

-- 
Jani Nikula, Intel Open Source Graphics Center