On Wed, 2016-10-26 at 08:37 +0200, Daniel Vetter wrote:
> On Mon, Oct 24, 2016 at 09:18:36PM -0700, Dhinakaran Pandiyan 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.
>
> Please insert a full Bspec citation here so that we can find where this is
> documented in the future. Both where in Bspec it is, and then just quote
> the full text with the explanation and put that into the commit message.
>
> Otherwise there's no way we'll ever find this again in the future.
> -Daniel
>
This particular update has not landed in BSpec yet. I will update the
commit message and re-send the patches after they are reviewed.
> >
> > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/i915_reg.h | 5 +++++
> > drivers/gpu/drm/i915/intel_ddi.c | 38 ++++++++++++++++++++++++++++++++++++++
> > drivers/gpu/drm/i915/intel_drv.h | 2 ++
> > 3 files changed, 45 insertions(+)
> >
> > 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_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index fb18d69..84c91c1 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -1858,6 +1858,38 @@ void intel_ddi_fdi_post_disable(struct intel_encoder *intel_encoder,
> > I915_WRITE(FDI_RX_CTL(PIPE_A), val);
> > }
> >
> > +void gen9_enable_dp_audio_stall_fix(struct intel_crtc_state *pipe_config)
> > +{
> > + struct drm_i915_private *dev_priv =
> > + to_i915(pipe_config->base.crtc->dev);
> > + enum transcoder cpu_transcoder = pipe_config->cpu_transcoder;
> > + uint32_t temp;
> > +
> > + if (intel_crtc_has_dp_encoder(pipe_config) &&
> > + pipe_config->port_clock >= 54000) {
> > +
> > + temp = I915_READ(CHICKEN_TRANS(cpu_transcoder));
> > + temp |= SPARE_13;
> > + I915_WRITE(CHICKEN_TRANS(cpu_transcoder), temp);
> > + }
> > +}
> > +
> > +void gen9_disable_dp_audio_stall_fix(struct intel_crtc_state *pipe_config)
> > +{
> > + struct drm_i915_private *dev_priv =
> > + to_i915(pipe_config->base.crtc->dev);
> > + enum transcoder cpu_transcoder = pipe_config->cpu_transcoder;
> > + uint32_t temp;
> > +
> > + if (intel_crtc_has_dp_encoder(pipe_config) &&
> > + pipe_config->port_clock >= 54000) {
> > +
> > + temp = I915_READ(CHICKEN_TRANS(cpu_transcoder));
> > + temp &= ~SPARE_13;
> > + I915_WRITE(CHICKEN_TRANS(cpu_transcoder), temp);
> > + }
> > +}
> > +
> > static void intel_enable_ddi(struct intel_encoder *intel_encoder,
> > struct intel_crtc_state *pipe_config,
> > struct drm_connector_state *conn_state)
> > @@ -1893,6 +1925,9 @@ static void intel_enable_ddi(struct intel_encoder *intel_encoder,
> > }
> >
> > if (intel_crtc->config->has_audio) {
> > + if (IS_GEN9(dev_priv))
> > + gen9_enable_dp_audio_stall_fix(pipe_config);
> > +
> > intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
> > intel_audio_codec_enable(intel_encoder);
> > }
> > @@ -1912,6 +1947,9 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder,
> > if (intel_crtc->config->has_audio) {
> > intel_audio_codec_disable(intel_encoder);
> > intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO);
> > +
> > + if (IS_GEN9(dev_priv))
> > + gen9_disable_dp_audio_stall_fix(old_crtc_state);
> > }
> >
> > if (type == INTEL_OUTPUT_EDP) {
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 4e90b07..ef02c62 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1189,6 +1189,8 @@ unsigned int intel_fb_align_height(struct drm_device *dev,
> > uint64_t fb_format_modifier);
> > u32 intel_fb_stride_alignment(const struct drm_i915_private *dev_priv,
> > uint64_t fb_modifier, uint32_t pixel_format);
> > +void gen9_enable_dp_audio_stall_fix(struct intel_crtc_state *pipe_config);
> > +void gen9_disable_dp_audio_stall_fix(struct intel_crtc_state *pipe_config);
> >
> > /* intel_audio.c */
> > void intel_init_audio_hooks(struct drm_i915_private *dev_priv);
> > --
> > 2.7.4
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
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