[Intel-gfx] [PATCH] drm/i915: 4K audio N value incorrect at 29.97 and 23.98 refresh rate

[Jani Nikula]

On Thu, 08 Oct 2015, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Wed, Oct 07, 2015 at 02:38:29PM -0700, clinton.a.taylor at intel.com wrote:
>> From: Clint Taylor <clinton.a.taylor at intel.com>
>> 
>> The TMDS_296M define was computing as 296704 but the mode->clock is
>> 296700 as defined by EDID. Adjusted define to allow correct detection
>> of the need to program the correct N value for 29.97 and 23.98 refresh
>> rate.
>> 
>> Signed-off-by: Clint Taylor <clinton.a.taylor at intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_audio.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
>> index 56c2f54..419c979 100644
>> --- a/drivers/gpu/drm/i915/intel_audio.c
>> +++ b/drivers/gpu/drm/i915/intel_audio.c
>> @@ -75,7 +75,7 @@ static const struct {
>>  
>>  /* HDMI N/CTS table */
>>  #define TMDS_297M 297000
>> -#define TMDS_296M DIV_ROUND_UP(297000 * 1000, 1001)
>> +#define TMDS_296M 296700
>
> Hmm. I think we might want to fix up the mode instead. Let me post a few
> patches, and let's see what people think...

We might actually want to queue this up for v4.3 as the immediate fix,
as I feel it's doubtful your other patches will make it to v4.3.

If Someone(tm) provided their r-b that is.

BR,
Jani.


>
>>  static const struct {
>>  	int sample_rate;
>>  	int clock;
>> -- 
>> 1.7.9.5
>> 
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>
> -- 
> Ville Syrjälä
> Intel OTC
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-- 
Jani Nikula, Intel Open Source Technology Center