Re: [Intel-gfx] [PATCH 14/22] drm/i915/audio: Do the vblank waits

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

On Tue, 11 Oct 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> The spec tells us to do a bunch of vblank waits in the audio
> enable/disable sequences. Make it so.
>
> The FIXMEs are nonsense since we do the audio disable very
> early and enable very late, so vblank interrupts are in fact
> enabled when we do this.
>
> TODO not sure we actually want these since we don't even rely
> on the hw ELD buffer, and these might be there just to give
> the audio side a bit of time to respond to the unsol events.
> OTOH they might be really needed for some other reason.

*shrug*

Acked-by: Jani Nikula <jani.nikula@intel.com>

>
> 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>
> ---
>  drivers/gpu/drm/i915/display/intel_audio.c | 31 +++++++++++++---------
>  1 file changed, 18 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_audio.c b/drivers/gpu/drm/i915/display/intel_audio.c
> index 0a1ba10fc20d..4eb5589a0f89 100644
> --- a/drivers/gpu/drm/i915/display/intel_audio.c
> +++ b/drivers/gpu/drm/i915/display/intel_audio.c
> @@ -318,10 +318,14 @@ static void g4x_audio_codec_disable(struct intel_encoder *encoder,
>  				    const struct drm_connector_state *old_conn_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
>  
>  	/* Invalidate ELD */
>  	intel_de_rmw(i915, G4X_AUD_CNTL_ST,
>  		     G4X_ELD_VALID, 0);
> +
> +	intel_crtc_wait_for_next_vblank(crtc);
> +	intel_crtc_wait_for_next_vblank(crtc);
>  }
>  
>  static void g4x_audio_codec_enable(struct intel_encoder *encoder,
> @@ -329,10 +333,13 @@ static void g4x_audio_codec_enable(struct intel_encoder *encoder,
>  				   const struct drm_connector_state *conn_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>  	struct drm_connector *connector = conn_state->connector;
>  	const u32 *eld = (const u32 *)connector->eld;
>  	int eld_buffer_size, len, i;
>  
> +	intel_crtc_wait_for_next_vblank(crtc);
> +
>  	intel_de_rmw(i915, G4X_AUD_CNTL_ST,
>  		     G4X_ELD_VALID | G4X_ELD_ADDRESS_MASK, 0);
>  
> @@ -466,6 +473,7 @@ static void hsw_audio_codec_disable(struct intel_encoder *encoder,
>  				    const struct drm_connector_state *old_conn_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
>  	enum transcoder cpu_transcoder = old_crtc_state->cpu_transcoder;
>  
>  	mutex_lock(&i915->display.audio.mutex);
> @@ -483,6 +491,9 @@ static void hsw_audio_codec_disable(struct intel_encoder *encoder,
>  	intel_de_rmw(i915, HSW_AUD_PIN_ELD_CP_VLD,
>  		     AUDIO_ELD_VALID(cpu_transcoder), 0);
>  
> +	intel_crtc_wait_for_next_vblank(crtc);
> +	intel_crtc_wait_for_next_vblank(crtc);
> +
>  	/* Disable audio presence detect */
>  	intel_de_rmw(i915, HSW_AUD_PIN_ELD_CP_VLD,
>  		     AUDIO_OUTPUT_ENABLE(cpu_transcoder), 0);
> @@ -604,6 +615,7 @@ static void hsw_audio_codec_enable(struct intel_encoder *encoder,
>  				   const struct drm_connector_state *conn_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>  	struct drm_connector *connector = conn_state->connector;
>  	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>  	const u32 *eld = (const u32 *)connector->eld;
> @@ -619,17 +631,12 @@ static void hsw_audio_codec_enable(struct intel_encoder *encoder,
>  	intel_de_rmw(i915, HSW_AUD_PIN_ELD_CP_VLD,
>  		     0, AUDIO_OUTPUT_ENABLE(cpu_transcoder));
>  
> +	intel_crtc_wait_for_next_vblank(crtc);
> +
>  	/* Invalidate ELD */
>  	intel_de_rmw(i915, HSW_AUD_PIN_ELD_CP_VLD,
>  		     AUDIO_ELD_VALID(cpu_transcoder), 0);
>  
> -	/*
> -	 * FIXME: We're supposed to wait for vblank here, but we have vblanks
> -	 * disabled during the mode set. The proper fix would be to push the
> -	 * rest of the setup into a vblank work item, queued here, but the
> -	 * infrastructure is not there yet.
> -	 */
> -
>  	/* Reset ELD address */
>  	intel_de_rmw(i915, HSW_AUD_DIP_ELD_CTRL(cpu_transcoder),
>  		     IBX_ELD_ADDRESS_MASK, 0);
> @@ -726,6 +733,9 @@ static void ilk_audio_codec_disable(struct intel_encoder *encoder,
>  		     IBX_ELD_VALID(port), 0);
>  
>  	mutex_unlock(&i915->display.audio.mutex);
> +
> +	intel_crtc_wait_for_next_vblank(crtc);
> +	intel_crtc_wait_for_next_vblank(crtc);
>  }
>  
>  static void ilk_audio_codec_enable(struct intel_encoder *encoder,
> @@ -744,12 +754,7 @@ static void ilk_audio_codec_enable(struct intel_encoder *encoder,
>  	if (drm_WARN_ON(&i915->drm, port == PORT_A))
>  		return;
>  
> -	/*
> -	 * FIXME: We're supposed to wait for vblank here, but we have vblanks
> -	 * disabled during the mode set. The proper fix would be to push the
> -	 * rest of the setup into a vblank work item, queued here, but the
> -	 * infrastructure is not there yet.
> -	 */
> +	intel_crtc_wait_for_next_vblank(crtc);
>  
>  	ilk_audio_regs_init(i915, pipe, &regs);

-- 
Jani Nikula, Intel Open Source Graphics Center