Re: [alsa-devel] [PATCH] drm/i915: set proper N/CTS in modeset

On Fri, 11 Sep 2015, libin.yang@intel.com wrote:

From: Libin Yang libin.yang@intel.com

When modeset occurs and the TMDS frequency is set to some speical values, the N/CTS need to be set manually if audio is playing.

Signed-off-by: Libin Yang libin.yang@intel.com

drivers/gpu/drm/i915/intel_audio.c | 56 ++++++++++++++++++++++++++++++++------ include/drm/i915_component.h | 10 +++++++ 2 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c index e3c32ce..a12bf57 100644 --- a/drivers/gpu/drm/i915/intel_audio.c +++ b/drivers/gpu/drm/i915/intel_audio.c @@ -128,6 +128,20 @@ static int audio_config_get_n(const struct drm_display_mode *mode, int rate) return 0; }

+static uint32_t audio_config_setup_n_reg(int n, uint32_t val) +{

• int n_low, n_up;
• uint32_t tmp = val;
• n_low = n & 0xfff;
• n_up = (n >> 12) & 0xff;
• tmp &= ~(AUD_CONFIG_UPPER_N_MASK | AUD_CONFIG_LOWER_N_MASK);
• tmp |= ((n_up << AUD_CONFIG_UPPER_N_SHIFT) |

• 	(n_low << AUD_CONFIG_LOWER_N_SHIFT) |
  

• 	AUD_CONFIG_N_PROG_ENABLE);
  

• return tmp;

+}

/* check whether N/CTS/M need be set manually */ static bool audio_rate_need_prog(struct intel_crtc *crtc, struct drm_display_mode *mode) @@ -262,9 +276,14 @@ static void hsw_audio_codec_enable(struct drm_connector *connector, struct drm_i915_private *dev_priv = connector->dev->dev_private; struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc); enum pipe pipe = intel_crtc->pipe;

• struct i915_audio_component *acomp = dev_priv->audio_component; const uint8_t *eld = connector->eld;

• struct intel_digital_port *intel_dig_port =

• enc_to_dig_port(&encoder->base);
  

• enum port port = intel_dig_port->port; uint32_t tmp; int len, i;

• int n, rate;

  DRM_DEBUG_KMS("Enable audio codec on pipe %c, %u bytes ELD\n", pipe_name(pipe), drm_eld_size(eld));

@@ -302,12 +321,29 @@ static void hsw_audio_codec_enable(struct drm_connector *connector, /* Enable timestamps */ tmp = I915_READ(HSW_AUD_CFG(pipe)); tmp &= ~AUD_CONFIG_N_VALUE_INDEX;

• tmp &= ~AUD_CONFIG_N_PROG_ENABLE; tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK; if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT)) tmp |= AUD_CONFIG_N_VALUE_INDEX; else tmp |= audio_config_hdmi_pixel_clock(mode);

• tmp &= ~AUD_CONFIG_N_PROG_ENABLE;

• if (audio_rate_need_prog(intel_crtc, mode)) {

• if (!acomp)
  

• 	rate = 0;
  

• else if (port >= PORT_A && port <= PORT_E)
  

• 	rate = acomp->aud_sample_rate[port];
  

• else {
  

• 	DRM_ERROR("invalid port: %d\n", port);
  

• 	rate = 0;
  

• }
  

• n = audio_config_get_n(mode, rate);
  

• if (n != 0)
  

• 	tmp = audio_config_setup_n_reg(n, tmp);
  

• else
  

• 	DRM_DEBUG_KMS("no suitable N value is found\n");
  

• }

• I915_WRITE(HSW_AUD_CFG(pipe), tmp);

  mutex_unlock(&dev_priv->av_mutex);

@@ -594,9 +630,10 @@ static int i915_audio_component_sync_audio_rate(struct device *dev, struct intel_digital_port *intel_dig_port; struct intel_crtc *crtc; struct drm_display_mode *mode;

• struct i915_audio_component *acomp = dev_priv->audio_component; enum pipe pipe = -1; u32 tmp;

• int n_low, n_up, n;

• int n;

  /* HSW, BDW SKL need this fix */ if (!IS_SKYLAKE(dev_priv) &&

@@ -630,6 +667,9 @@ static int i915_audio_component_sync_audio_rate(struct device *dev, pipe_name(pipe), port_name(port)); mode = &crtc->config->base.adjusted_mode;

• /* port must be valid now, otherwise the pipe will be invalid */
• acomp->aud_sample_rate[port] = rate;
• /* 2. check whether to set the N/CTS/M manually or not */ if (!audio_rate_need_prog(crtc, mode)) { tmp = I915_READ(HSW_AUD_CFG(pipe));

@@ -649,15 +689,10 @@ static int i915_audio_component_sync_audio_rate(struct device *dev, mutex_unlock(&dev_priv->av_mutex); return 0; }

• n_low = n & 0xfff;

• n_up = (n >> 12) & 0xff;

• /* 4. set the N/CTS/M */

• /* 3. set the N/CTS/M */ tmp = I915_READ(HSW_AUD_CFG(pipe));

• tmp &= ~(AUD_CONFIG_UPPER_N_MASK | AUD_CONFIG_LOWER_N_MASK);
• tmp |= ((n_up << AUD_CONFIG_UPPER_N_SHIFT) |

• 	(n_low << AUD_CONFIG_LOWER_N_SHIFT) |
  

• 	AUD_CONFIG_N_PROG_ENABLE);
  

• tmp = audio_config_setup_n_reg(n, tmp); I915_WRITE(HSW_AUD_CFG(pipe), tmp);

  mutex_unlock(&dev_priv->av_mutex);

@@ -678,6 +713,7 @@ static int i915_audio_component_bind(struct device *i915_dev, { struct i915_audio_component *acomp = data; struct drm_i915_private *dev_priv = dev_to_i915(i915_dev);

• int i;

  if (WARN_ON(acomp->ops || acomp->dev)) return -EEXIST;

@@ -685,6 +721,8 @@ static int i915_audio_component_bind(struct device *i915_dev, drm_modeset_lock_all(dev_priv->dev); acomp->ops = &i915_audio_component_ops; acomp->dev = i915_dev;

• for (i = 0; i < I915_MAX_PORTS; i++)

• acomp->aud_sample_rate[i] = 0;
  

  dev_priv->audio_component = acomp; drm_modeset_unlock_all(dev_priv->dev);

diff --git a/include/drm/i915_component.h b/include/drm/i915_component.h index e6d35d7..89dc7d6 100644 --- a/include/drm/i915_component.h +++ b/include/drm/i915_component.h @@ -24,8 +24,18 @@ #ifndef _I915_COMPONENT_H_ #define _I915_COMPONENT_H_

+/* MAX_PORT is the number of port

• • It must be sync with I915_MAX_PORTS defined i915_drv.h
• • 5 should be enough as only HSW, BDW, SKL need such fix.

You should probably add BUILD_BUG_ON(MAX_PORTS != I915_MAX_PORTS) somewhere near the loop above. Or at least change I915_MAX_PORTS to ARRAY_SIZE(acomp->aud_sample_rate) in the loop to not run over the array if MAX_PORTS gets out of sync.

With that addressed one way or another, this is

Reviewed-by: Jani Nikula jani.nikula@intel.com

• */

+#define MAX_PORTS 5

struct i915_audio_component { struct device *dev;

• /**

• * @aud_sample_rate: the array of audio sample rate per port
  

• */
  

• int aud_sample_rate[MAX_PORTS];

  const struct i915_audio_component_ops { struct module *owner;

-- 1.9.1