On Wed, 26 Oct 2016, Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> wrote:
> Enabling DP audio stall fix is necessary to play audio over DP HBR2. So,
> let's set this bit right before enabling the audio codec. Playing audio
> without setting this bit results in pipe FIFO underruns.
>
> This workaround is applicable only for audio sample rates up to 96kHz. For
> frequencies above 96kHz, this is insufficient and cdclk should be increased
> to at least 432 MHz, just like BDW. Since, the audio driver does not
> support sample rates > 48 kHz, we are safe with this fix for now.
Do we still need this patch now that these two have been pushed?
b30ce9e0552a drm/i915/dp: BDW cdclk fix for DP audio
9c7540241885 drm/i915/dp: Extend BDW DP audio workaround to GEN9 platforms
BR,
Jani.
>
> v2: Inlined the code change within hsw_audio_codec_enable() (Jani)
> Fixed the port clock typo
> Added TODO comment
> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 5 +++++
> drivers/gpu/drm/i915/intel_audio.c | 30 +++++++++++++++++++++++++++++-
> 2 files changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 00efaa1..76dac48 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6236,6 +6236,11 @@ enum {
> #define SLICE_ECO_CHICKEN0 _MMIO(0x7308)
> #define PIXEL_MASK_CAMMING_DISABLE (1 << 14)
>
> +#define _CHICKEN_TRANS_A 0x420C0
> +#define _CHICKEN_TRANS_B 0x420C4
> +#define CHICKEN_TRANS(tran) _MMIO_TRANS(tran, _CHICKEN_TRANS_A, _CHICKEN_TRANS_B)
> +#define SPARE_13 (1<<13)
> +
> /* WaCatErrorRejectionIssue */
> #define GEN7_SQ_CHICKEN_MBCUNIT_CONFIG _MMIO(0x9030)
> #define GEN7_SQ_CHICKEN_MBCUNIT_SQINTMOB (1<<11)
> diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
> index 7093cfb..894f11e 100644
> --- a/drivers/gpu/drm/i915/intel_audio.c
> +++ b/drivers/gpu/drm/i915/intel_audio.c
> @@ -283,6 +283,8 @@ static void hsw_audio_codec_disable(struct intel_encoder *encoder)
> {
> struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
> + struct intel_crtc_state *crtc_config = intel_crtc->config;
> + enum transcoder cpu_transcoder = crtc_config->cpu_transcoder;
> enum pipe pipe = intel_crtc->pipe;
> uint32_t tmp;
>
> @@ -290,13 +292,21 @@ static void hsw_audio_codec_disable(struct intel_encoder *encoder)
>
> mutex_lock(&dev_priv->av_mutex);
>
> + /*Disable DP audio stall fix for HBR2*/
> + if (IS_GEN9(dev_priv) && intel_crtc_has_dp_encoder(crtc_config) &&
> + crtc_config->port_clock >= 540000) {
> + tmp = I915_READ(CHICKEN_TRANS(cpu_transcoder));
> + tmp &= ~SPARE_13;
> + I915_WRITE(CHICKEN_TRANS(cpu_transcoder), tmp);
> + }
> +
> /* Disable timestamps */
> tmp = I915_READ(HSW_AUD_CFG(pipe));
> tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
> tmp |= AUD_CONFIG_N_PROG_ENABLE;
> tmp &= ~AUD_CONFIG_UPPER_N_MASK;
> tmp &= ~AUD_CONFIG_LOWER_N_MASK;
> - if (intel_crtc_has_dp_encoder(intel_crtc->config))
> + if (intel_crtc_has_dp_encoder(crtc_config))
> tmp |= AUD_CONFIG_N_VALUE_INDEX;
> I915_WRITE(HSW_AUD_CFG(pipe), tmp);
>
> @@ -315,6 +325,8 @@ static void hsw_audio_codec_enable(struct drm_connector *connector,
> {
> struct drm_i915_private *dev_priv = to_i915(connector->dev);
> struct intel_crtc *intel_crtc = to_intel_crtc(intel_encoder->base.crtc);
> + struct intel_crtc_state *crtc_config = intel_crtc->config;
> + enum transcoder cpu_transcoder = crtc_config->cpu_transcoder;
> enum pipe pipe = intel_crtc->pipe;
> enum port port = intel_encoder->port;
> const uint8_t *eld = connector->eld;
> @@ -326,6 +338,22 @@ static void hsw_audio_codec_enable(struct drm_connector *connector,
>
> mutex_lock(&dev_priv->av_mutex);
>
> + /* Enable DP audio stall fix for HBR2
> + *
> + * TODO: This workaround is applicable only for audio sample rates up
> + * to 96kHz. For frequencies above 96kHz, this is insufficient and
> + * cdclk should be increased to at least 432 MHz, just like BDW. Since,
> + * the audio driver does not support sample rates > 48 kHz, we are safe
> + * with this fix for now.
> + */
> +
> + if (IS_GEN9(dev_priv) && intel_crtc_has_dp_encoder(crtc_config) &&
> + crtc_config->port_clock >= 540000) {
> + tmp = I915_READ(CHICKEN_TRANS(cpu_transcoder));
> + tmp |= SPARE_13;
> + I915_WRITE(CHICKEN_TRANS(cpu_transcoder), tmp);
> + }
> +
> /* Enable audio presence detect, invalidate ELD */
> tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
> tmp |= AUDIO_OUTPUT_ENABLE(pipe);
--
Jani Nikula, Intel Open Source Technology Center
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