[alsa-devel] [Intel-gfx] [PATCH v5 2/4] drm/i915: implement sync_audio_rate callback
Ville Syrjälä
ville.syrjala at linux.intel.com
Mon Aug 24 14:53:19 CEST 2015
On Mon, Aug 24, 2015 at 02:38:14AM +0000, Yang, Libin wrote:
> > -----Original Message-----
> > From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com]
> > Sent: Friday, August 21, 2015 11:14 PM
> > To: Yang, Libin
> > Cc: alsa-devel at alsa-project.org; tiwai at suse.de; intel-
> > gfx at lists.freedesktop.org; daniel.vetter at ffwll.ch;
> > jani.nikula at linux.intel.com
> > Subject: Re: [Intel-gfx] [PATCH v5 2/4] drm/i915: implement
> > sync_audio_rate callback
> >
> > On Tue, Aug 18, 2015 at 02:51:52PM +0800, libin.yang at intel.com
> > wrote:
> > > From: Libin Yang <libin.yang at intel.com>
> > >
> > > HDMI audio may not work at some frequencies
> > > with the HW provided N/CTS.
> > >
> > > This patch sets the proper N value for the
> > > given audio sample rate at the impacted frequencies.
> > > At other frequencies, it will use the N/CTS value
> > > which HW provides.
> > >
> > > Signed-off-by: Libin Yang <libin.yang at intel.com>
> > > ---
> > > drivers/gpu/drm/i915/intel_audio.c | 119
> > +++++++++++++++++++++++++++++++++++++
> > > 1 file changed, 119 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_audio.c
> > b/drivers/gpu/drm/i915/intel_audio.c
> > > index dc32cf4..96b97be 100644
> > > --- a/drivers/gpu/drm/i915/intel_audio.c
> > > +++ b/drivers/gpu/drm/i915/intel_audio.c
> > > @@ -68,6 +68,31 @@ static const struct {
> > > { 148500, AUD_CONFIG_PIXEL_CLOCK_HDMI_148500 },
> > > };
> > >
> > > +/* HDMI N/CTS table */
> > > +#define TMDS_297M 297000
> > > +#define TMDS_296M DIV_ROUND_UP(297000 * 1000, 1001)
> >
> > I don't really like the defines.
>
> I agree it's not a good name. Do you have some suggestions?
I'd probably just have used raw numbers myself.
>
> >
> > > +static const struct {
> > > + int sample_rate;
> > > + int clock;
> > > + int n;
> > > + int cts;
> > > +} aud_ncts[] = {
> > > + { 44100, TMDS_296M, 4459, 234375 },
> > > + { 44100, TMDS_297M, 4704, 247500 },
> > > + { 48000, TMDS_296M, 5824, 281250 },
> > > + { 48000, TMDS_297M, 5120, 247500 },
> > > + { 32000, TMDS_296M, 5824, 421875 },
> > > + { 32000, TMDS_297M, 3072, 222750 },
> > > + { 88200, TMDS_296M, 8918, 234375 },
> > > + { 88200, TMDS_297M, 9408, 247500 },
> > > + { 96000, TMDS_296M, 11648, 281250 },
> > > + { 96000, TMDS_297M, 10240, 247500 },
> > > + { 176400, TMDS_296M, 17836, 234375 },
> > > + { 176400, TMDS_297M, 18816, 247500 },
> > > + { 44100, TMDS_296M, 23296, 281250 },
> > > + { 44100, TMDS_297M, 20480, 247500 },
> > > +};
> >
> > Last two should be 192 kHz. All the other values seem to match the
> > spec.
>
> Oh, my typo. Thanks for pointing it out.
>
> >
> > These do assume 8bpc, but as the spec doesn't even specify N/CTS
> > values for deep color modes @ 297MHz, so I suppose the expectations
> > is
> > that the max TMDS clock will never be so high as to allow them.
> >
> > If/when we start using manual programming for other TMDS clock
> > rates
> > we'll need to consider 12bpc as well.
>
> These values are recommended from HDMI spec. It's not related
> to the bpp. Am I wrong? I'm find the value from HDMISpecification
> 1.4: table 7-1, table 7-2 and table 7-3.
There are separate tables for deep color modes in appendix D. Tables
D-1 through D-3 are of interest to us since we can only do the 12bpc
deep color mode.
>
> >
> > > +
> > > /* get AUD_CONFIG_PIXEL_CLOCK_HDMI_* value for mode */
> > > static u32 audio_config_hdmi_pixel_clock(struct drm_display_mode
> > *mode)
> > > {
> > > @@ -90,6 +115,31 @@ static u32
> > audio_config_hdmi_pixel_clock(struct drm_display_mode *mode)
> > > return hdmi_audio_clock[i].config;
> > > }
> > >
> > > +static int audio_config_get_n(struct drm_display_mode *mode, int
> > rate)
> >
> > mode can be const.
>
> OK. I will change it.
>
> >
> > > +{
> > > + int i;
> > > +
> > > + for (i = 0; i < ARRAY_SIZE(aud_ncts); i++) {
> > > + if ((rate == aud_ncts[i].sample_rate) &&
> > > + (mode->clock == aud_ncts[i].clock)) {
> > > + return aud_ncts[i].n;
> > > + }
> > > + }
> > > + return 0;
> > > +}
> > > +
> > > +/* check whether N/CTS/M need be set manually */
> > > +static bool audio_rate_need_prog(struct intel_crtc *crtc,
> > > + struct drm_display_mode
> > *mode)
> > > +{
> > > + if (((mode->clock == TMDS_297M) ||
> > > + (mode->clock == TMDS_296M)) &&
> > > + intel_pipe_has_type(crtc, INTEL_OUTPUT_HDMI))
> > > + return true;
> > > + else
> > > + return false;
> > > +}
> > > +
> > > static bool intel_eld_uptodate(struct drm_connector *connector,
> > > int reg_eldv, uint32_t bits_eldv,
> > > int reg_elda, uint32_t bits_elda,
> > > @@ -514,12 +564,81 @@ static int
> > i915_audio_component_get_cdclk_freq(struct device *dev)
> > > return ret;
> > > }
> > >
> > > +static int i915_audio_component_sync_audio_rate(struct device
> > *dev,
> > > + int port, int rate)
> > > +{
> > > + struct drm_i915_private *dev_priv = dev_to_i915(dev);
> > > + struct drm_device *drm_dev = dev_priv->dev;
> > > + struct intel_encoder *intel_encoder;
> > > + struct intel_digital_port *intel_dig_port;
> > > + struct intel_crtc *crtc;
> > > + struct drm_display_mode *mode;
> > > + enum pipe pipe = -1;
> > > + u32 tmp;
> > > + int n_low, n_up, n;
> > > +
> > > + /* 1. get the pipe */
> > > + for_each_intel_encoder(drm_dev, intel_encoder) {
> > > + if (intel_encoder->type != INTEL_OUTPUT_HDMI)
> > > + continue;
> > > + intel_dig_port = enc_to_dig_port(&intel_encoder-
> > >base);
> > > + if (port == intel_dig_port->port) {
> > > + crtc = to_intel_crtc(intel_encoder->base.crtc);
> >
> > This sort of thing would need some locking to safely start digging at
> > the modeset state.
> >
> > I would probably not do that, and instead add some new lock(s) for this.
> > The modeset code would then fill out some relevant information
> > protected
> > by that same lock, and this function could then go look at it without
> > having to worry about the rest of modeset locking/state.
>
> >From audio side, there is no competition when calling the function,
> I think.
> For protecting the competition between audio and gfx driver,
> it seems we need use the lock from gfx side. Do you have suggested
> lock I can use?
To do it like this we'd need pretty much all the modeset locks, which
to me feels a bit troublesome if the audio driver can call this at
any point. So I suggested that we may want to add some kind of new
audio lock to i915.
>
> >
> > > + if (!crtc) {
> > > + DRM_DEBUG_KMS("%s: crtc is
> > NULL\n", __func__);
> > > + continue;
> > > + }
> > > + pipe = crtc->pipe;
> > > + break;
> > > + }
> > > + }
> > > +
> > > + if (pipe == INVALID_PIPE) {
> > > + DRM_DEBUG_KMS("no pipe for the port %c\n",
> > port_name(port));
> > > + return -ENODEV;
> > > + }
> > > + DRM_DEBUG_KMS("pipe %c connects port %c\n",
> > > + pipe_name(pipe), port_name(port));
> > > + mode = &crtc->config->base.adjusted_mode;
> > > +
> > > + /* 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));
> > > + tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
> > > + I915_WRITE(HSW_AUD_CFG(pipe), tmp);
> >
> > This stuff would need to be abstracted to work on pre-HSW too.
>
> Right, I need judge the platform firstly.
>
> >
> > > + return 0;
> > > + }
> > > +
> > > + n = audio_config_get_n(mode, rate);
> > > + if (n == 0) {
> > > + DRM_DEBUG_KMS("Using automatic mode for N value
> > on port %c\n",
> > > + port_name(port));
> > > + tmp = I915_READ(HSW_AUD_CFG(pipe));
> > > + tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
> > > + I915_WRITE(HSW_AUD_CFG(pipe), tmp);
> > > + return 0;
> > > + }
> > > + n_low = n & 0xfff;
> > > + n_up = (n >> 12) & 0xff;
> > > +
> > > + /* 4. 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);
> > > + I915_WRITE(HSW_AUD_CFG(pipe), tmp);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static const struct i915_audio_component_ops
> > i915_audio_component_ops = {
> > > .owner = THIS_MODULE,
> > > .get_power = i915_audio_component_get_power,
> > > .put_power = i915_audio_component_put_power,
> > > .codec_wake_override =
> > i915_audio_component_codec_wake_override,
> > > .get_cdclk_freq = i915_audio_component_get_cdclk_freq,
> > > + .sync_audio_rate = i915_audio_component_sync_audio_rate,
> > > };
> > >
> > > static int i915_audio_component_bind(struct device *i915_dev,
> > > --
> > > 1.9.1
> > >
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx at lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > --
> > Ville Syrjälä
> > Intel OTC
--
Ville Syrjälä
Intel OTC
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