Re: [PATCH v2 2/2] drm/i915: Add N & CTS values for 10/12 bit deep color

[Aditya Swarup <aditya.swarup@intel.com>]

On Wed, May 15, 2019 at 05:40:10PM +0300, Jani Nikula wrote:
> On Tue, 02 Apr 2019, Aditya Swarup <aditya.swarup@intel.com> wrote:
> > Adding N & CTS values for 10/12 bit deep color from Appendix C
> > table in HDMI 2.0 spec. The correct values for N is not chosen
> > automatically by hardware for deep color modes.
> >
> > v2: Remove redundant code and make it generic.(Jani)
> >
> > Signed-off-by: Aditya Swarup <aditya.swarup@intel.com>
> > Cc: Clint Taylor <Clinton.A.Taylor@intel.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_audio.c | 82 +++++++++++++++++++++++++-----
> >  1 file changed, 69 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
> > index 502b57ce72ab..ad53b04fa5a2 100644
> > --- a/drivers/gpu/drm/i915/intel_audio.c
> > +++ b/drivers/gpu/drm/i915/intel_audio.c
> > @@ -70,6 +70,13 @@ struct dp_aud_n_m {
> >  	u16 n;
> >  };
> >  
> > +struct hdmi_aud_ncts_table {
> 
> The struct itself is not a table. Just make it struct hdmi_ncts or
> something.
Will do it in the next spin.
> 
> > +	int sample_rate;
> > +	int clock;
> > +	int n;
> > +	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 },
> > @@ -146,12 +153,7 @@ static const struct {
> >  #define TMDS_594M 594000
> >  #define TMDS_593M 593407
> >  
> > -static const struct {
> > -	int sample_rate;
> > -	int clock;
> > -	int n;
> > -	int cts;
> > -} hdmi_aud_ncts[] = {
> > +static const struct hdmi_aud_ncts_table hdmi_aud_ncts_24bpp[] = {
> >  	{ 32000, TMDS_296M, 5824, 421875 },
> >  	{ 32000, TMDS_297M, 3072, 222750 },
> >  	{ 32000, TMDS_593M, 5824, 843750 },
> > @@ -182,6 +184,49 @@ static const struct {
> >  	{ 192000, TMDS_594M, 24576, 594000 },
> >  };
> >  
> > +/* Appendix C - N & CTS values for deep color from HDMI 2.0 spec*/
> > +/* HDMI N/CTS table for 10 bit deep color(30 bpp)*/
> > +#define TMDS_371M 371250
> > +#define TMDS_370M 370878
> > +
> > +static const struct hdmi_aud_ncts_table hdmi_aud_ncts_30bpp[] = {
> > +	{ 32000, TMDS_370M, 5824, 527344 },
> 
> N should be 11648?
The value in the struct is correct. It is 5824 - Appendix C Table C-1 Pg
234, for 371.25/1.001 and f = 32kHz => N = 5824
> 
> > +	{ 32000, TMDS_371M, 6144, 556875 },
> > +	{ 44100, TMDS_370M, 8918, 585938 },
> 
> N 17836
Value in the table is correct.
> 
> > +	{ 44100, TMDS_371M, 4704, 309375 },
> > +	{ 88200, TMDS_370M, 17836, 585938 },
> 
> N 35672
Value in the table is correct.
> 
> > +	{ 88200, TMDS_371M, 9408, 309375 },
> > +	{ 176400, TMDS_370M, 35672, 585938 },
> 
> N 71344
Value in the table is correct.
> 
> > +	{ 176400, TMDS_371M, 18816, 309375 },
> > +	{ 48000, TMDS_370M, 11648, 703125 },
> > +	{ 48000, TMDS_371M, 5120, 309375 },
> > +	{ 96000, TMDS_370M, 23296, 703125 },
> > +	{ 96000, TMDS_371M, 10240, 309375 },
> > +	{ 192000, TMDS_370M, 46592, 703125 },
> > +	{ 192000, TMDS_371M, 20480, 309375 },
> > +};
> > +
> > +/* HDMI N/CTS table for 12 bit deep color(36 bpp)*/
> > +#define TMDS_445_5M 445500
> > +#define TMDS_445M 445054
> > +
> > +static const struct hdmi_aud_ncts_table hdmi_aud_ncts_36bpp[] = {
> > +	{ 32000, TMDS_445M, 5824, 632813 },
> > +	{ 32000, TMDS_445_5M, 4096, 445500 },
> > +	{ 44100, TMDS_445M, 8918, 703125 },
> > +	{ 44100, TMDS_445_5M, 4704, 371250 },
> > +	{ 88200, TMDS_445M, 17836, 703125 },
> > +	{ 88200, TMDS_445_5M, 9408, 371250 },
> > +	{ 176400, TMDS_445M, 35672, 703125 },
> > +	{ 176400, TMDS_445_5M, 18816, 371250 },
> > +	{ 48000, TMDS_445M, 5824, 421875 },
> > +	{ 48000, TMDS_445_5M, 5120, 371250 },
> > +	{ 96000, TMDS_445M, 11648, 421875 },
> > +	{ 96000, TMDS_445_5M, 10240, 371250 },
> > +	{ 192000, TMDS_445M, 23296, 421875 },
> > +	{ 192000, TMDS_445_5M, 20480, 371250 },
> > +};
> > +
> >  /* get AUD_CONFIG_PIXEL_CLOCK_HDMI_* value for mode */
> >  static u32 audio_config_hdmi_pixel_clock(const struct intel_crtc_state *crtc_state)
> >  {
> > @@ -210,16 +255,27 @@ static u32 audio_config_hdmi_pixel_clock(const struct intel_crtc_state *crtc_sta
> >  static int audio_config_hdmi_get_n(const struct intel_crtc_state *crtc_state,
> >  				   int rate)
> >  {
> > -	const struct drm_display_mode *adjusted_mode =
> > -		&crtc_state->base.adjusted_mode;
> > -	int i;
> > +	const struct hdmi_aud_ncts_table *hdmi_ncts_table;
> > +	int i, size = 0;
> 
> Unnecessary initialization.
> 
> > +
> > +	if (crtc_state->pipe_bpp == 36) {
> > +		hdmi_ncts_table = hdmi_aud_ncts_36bpp;
> > +		size = ARRAY_SIZE(hdmi_aud_ncts_36bpp);
> > +	} else if (crtc_state->pipe_bpp == 30) {
> > +		hdmi_ncts_table = hdmi_aud_ncts_30bpp;
> > +		size = ARRAY_SIZE(hdmi_aud_ncts_30bpp);
> > +	} else {
> > +		hdmi_ncts_table = hdmi_aud_ncts_24bpp;
> > +		size = ARRAY_SIZE(hdmi_aud_ncts_24bpp);
> > +	}
> >  
> > -	for (i = 0; i < ARRAY_SIZE(hdmi_aud_ncts); i++) {
> > -		if (rate == hdmi_aud_ncts[i].sample_rate &&
> > -		    adjusted_mode->crtc_clock == hdmi_aud_ncts[i].clock) {
> > -			return hdmi_aud_ncts[i].n;
> > +	for (i = 0;  i < size; i++) {
>                     ^
> Superfluous space.
Will correct it in next spin.
> 
> 
> > +		if (rate == hdmi_ncts_table[i].sample_rate &&
> > +		    crtc_state->port_clock == hdmi_ncts_table[i].clock) {
> 
> Changing from adjusted_mode->crtc_clock to crtc_state->port_clock is a
> separate change that needs to be a separate patch.
I don't think it should be a separate change. Working with deep color
mode requires crtc_state->port_clock as it is scaled according to the
deep color mode set. Using adjusted_mode->crtc_clock is incorrect as it
doesn't account for deep color mode; we will have to multiply with
scaling factor for the set deep color mode which is superfluous.

I can add a comment in the commit message and comment before the if
block to explain the change. Let me know if it works?
> 
> 
> BR,
> Jani.
> 
> > +			return hdmi_ncts_table[i].n;
> >  		}
> >  	}
> > +
> >  	return 0;
> >  }
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center

Regards,
Aditya Swarup
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