Hello all,

Please ignore this version. I accidentally sent a version I was experimenting 
with. I will correct it in the next revision.
Sorry for the spam.


> -----Original Message-----
> From: Intel-gfx <intel-gfx-boun...@lists.freedesktop.org> On Behalf Of
> Chaitanya Kumar Borah
> Sent: Tuesday, April 30, 2024 2:04 PM
> To: intel-gfx@lists.freedesktop.org
> Cc: Vehmanen, Kai <kai.vehma...@intel.com>; Saarinen, Jani
> <jani.saari...@intel.com>; ville.syrj...@linux.intel.com;
> jani.nik...@linux.intel.com; Yang, Libin <libin.y...@intel.com>; Shankar, Uma
> <uma.shan...@intel.com>
> Subject: [PATCH] drm/i915/audio: Fix audio time stamp programming for DP
> 
> Intel hardware is capable of programming the Maud/Naud SDPs on its own
> based on real-time clocks. While doing so, it takes care of any deviations 
> from
> the theoretical values. Programming the registers explicitly with static 
> values
> can interfere with this logic. Therefore, let the HW decide the Maud and Naud
> SDPs on it's own.
> 
> Cc: sta...@vger.kernel.org # v5.17
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8097
> Co-developed-by: Kai Vehmanen <kai.vehma...@intel.com>
> Signed-off-by: Kai Vehmanen <kai.vehma...@intel.com>
> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.bo...@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_audio.c | 111 ++-------------------
>  1 file changed, 6 insertions(+), 105 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_audio.c
> b/drivers/gpu/drm/i915/display/intel_audio.c
> index 07e0c73204f3..12e2ba462077 100644
> --- a/drivers/gpu/drm/i915/display/intel_audio.c
> +++ b/drivers/gpu/drm/i915/display/intel_audio.c
> @@ -76,19 +76,6 @@ struct intel_audio_funcs {
>                                      struct intel_crtc_state *crtc_state);  };
> 
> -/* DP N/M table */
> -#define LC_810M      810000
> -#define LC_540M      540000
> -#define LC_270M      270000
> -#define LC_162M      162000
> -
> -struct dp_aud_n_m {
> -     int sample_rate;
> -     int clock;
> -     u16 m;
> -     u16 n;
> -};
> -
>  struct hdmi_aud_ncts {
>       int sample_rate;
>       int clock;
> @@ -96,60 +83,6 @@ struct hdmi_aud_ncts {
>       int cts;
>  };
> 
> -/* Values according to DP 1.4 Table 2-104 */ -static const struct dp_aud_n_m
> dp_aud_n_m[] = {
> -     { 32000, LC_162M, 1024, 10125 },
> -     { 44100, LC_162M, 784, 5625 },
> -     { 48000, LC_162M, 512, 3375 },
> -     { 64000, LC_162M, 2048, 10125 },
> -     { 88200, LC_162M, 1568, 5625 },
> -     { 96000, LC_162M, 1024, 3375 },
> -     { 128000, LC_162M, 4096, 10125 },
> -     { 176400, LC_162M, 3136, 5625 },
> -     { 192000, LC_162M, 2048, 3375 },
> -     { 32000, LC_270M, 1024, 16875 },
> -     { 44100, LC_270M, 784, 9375 },
> -     { 48000, LC_270M, 512, 5625 },
> -     { 64000, LC_270M, 2048, 16875 },
> -     { 88200, LC_270M, 1568, 9375 },
> -     { 96000, LC_270M, 1024, 5625 },
> -     { 128000, LC_270M, 4096, 16875 },
> -     { 176400, LC_270M, 3136, 9375 },
> -     { 192000, LC_270M, 2048, 5625 },
> -     { 32000, LC_540M, 1024, 33750 },
> -     { 44100, LC_540M, 784, 18750 },
> -     { 48000, LC_540M, 512, 11250 },
> -     { 64000, LC_540M, 2048, 33750 },
> -     { 88200, LC_540M, 1568, 18750 },
> -     { 96000, LC_540M, 1024, 11250 },
> -     { 128000, LC_540M, 4096, 33750 },
> -     { 176400, LC_540M, 3136, 18750 },
> -     { 192000, LC_540M, 2048, 11250 },
> -     { 32000, LC_810M, 1024, 50625 },
> -     { 44100, LC_810M, 784, 28125 },
> -     { 48000, LC_810M, 512, 16875 },
> -     { 64000, LC_810M, 2048, 50625 },
> -     { 88200, LC_810M, 1568, 28125 },
> -     { 96000, LC_810M, 1024, 16875 },
> -     { 128000, LC_810M, 4096, 50625 },
> -     { 176400, LC_810M, 3136, 28125 },
> -     { 192000, LC_810M, 2048, 16875 },
> -};
> -
> -static const struct dp_aud_n_m *
> -audio_config_dp_get_n_m(const struct intel_crtc_state *crtc_state, int rate) 
> -
> {
> -     int i;
> -
> -     for (i = 0; i < ARRAY_SIZE(dp_aud_n_m); i++) {
> -             if (rate == dp_aud_n_m[i].sample_rate &&
> -                 crtc_state->port_clock == dp_aud_n_m[i].clock)
> -                     return &dp_aud_n_m[i];
> -     }
> -
> -     return NULL;
> -}
> -
>  static const struct {
>       int clock;
>       u32 config;
> @@ -387,47 +320,15 @@ hsw_dp_audio_config_update(struct
> intel_encoder *encoder,
>                          const struct intel_crtc_state *crtc_state)  {
>       struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> -     struct i915_audio_component *acomp = i915-
> >display.audio.component;
>       enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> -     enum port port = encoder->port;
> -     const struct dp_aud_n_m *nm;
> -     int rate;
> -     u32 tmp;
> 
> -     rate = acomp ? acomp->aud_sample_rate[port] : 0;
> -     nm = audio_config_dp_get_n_m(crtc_state, rate);
> -     if (nm)
> -             drm_dbg_kms(&i915->drm, "using Maud %u, Naud %u\n",
> nm->m,
> -                         nm->n);
> -     else
> -             drm_dbg_kms(&i915->drm, "using automatic Maud,
> Naud\n");
> -
> -     tmp = intel_de_read(i915, HSW_AUD_CFG(cpu_transcoder));
> -     tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
> -     tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK;
> -     tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
> -     tmp |= AUD_CONFIG_N_VALUE_INDEX;
> -
> -     if (nm) {
> -             tmp &= ~AUD_CONFIG_N_MASK;
> -             tmp |= AUD_CONFIG_N(nm->n);
> -             tmp |= AUD_CONFIG_N_PROG_ENABLE;
> -     }
> -
> -     intel_de_write(i915, HSW_AUD_CFG(cpu_transcoder), tmp);
> -
> -     tmp = intel_de_read(i915,
> HSW_AUD_M_CTS_ENABLE(cpu_transcoder));
> -     tmp &= ~AUD_CONFIG_M_MASK;
> -     tmp &= ~AUD_M_CTS_M_VALUE_INDEX;
> -     tmp &= ~AUD_M_CTS_M_PROG_ENABLE;
> -
> -     if (nm) {
> -             tmp |= nm->m;
> -             tmp |= AUD_M_CTS_M_VALUE_INDEX;
> -             tmp |= AUD_M_CTS_M_PROG_ENABLE;
> -     }
> +     /* Enable time stamps. Let HW calculate Maud/Naud values */
> +     intel_de_rmw(i915, HSW_AUD_CFG(cpu_transcoder),
> +                  AUD_CONFIG_N_VALUE_INDEX |
> +                  AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK |
> +                  AUD_CONFIG_N_PROG_ENABLE,
> +                  AUD_CONFIG_N_VALUE_INDEX);
> 
> -     intel_de_write(i915, HSW_AUD_M_CTS_ENABLE(cpu_transcoder),
> tmp);
>  }
> 
>  static void
> --
> 2.25.1

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