[Intel-gfx] [PATCH v4 1/2] drm/i915/dp: Enable DP audio stall fix for gen9 platforms
Yang, Libin
libin.yang at intel.com
Fri Oct 28 06:43:49 UTC 2016
> -----Original Message-----
> From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf Of
> Pandiyan, Dhinakaran
> Sent: Thursday, October 27, 2016 2:14 AM
> To: ville.syrjala at linux.intel.com
> Cc: Nikula, Jani <jani.nikula at intel.com>; Kp, Jeeja <jeeja.kp at intel.com>;
> intel-gfx at lists.freedesktop.org; libin.yang at linux.intel.com
> Subject: Re: [Intel-gfx] [PATCH v4 1/2] drm/i915/dp: Enable DP audio stall fix
> for gen9 platforms
>
> On Wed, 2016-10-26 at 12:11 +0300, Ville Syrjälä wrote:
> > On Tue, Oct 25, 2016 at 07:37:36PM -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.
> > >
> > > 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.
> > >
> > > 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 at intel.com>
> > > ---
> > > 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.
> >
> > Where in the sound driver is this supposed 96kHz limit? I see a lot of
> > stuff for >96kHz in the code at least.
> >
>
> Libin/Jeeja can you help me here?
From audio driver side, 96KHz should be similar with 48KHz. I have test 88KHz,
it works. When I test 96KHz, it will be converted to 48KHz. Our audio QA
didn't test 88KHz and 96KHz and it is not in our support list.
How do you get the 'stuff for >96kHz in the code' message? It seems I can't
reproduce this message.
Regards,
Libin
>
>
> > > + */
> > > +
> > > + 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);
> > > --
> > > 2.7.4
> >
>
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