Re: [PATCH v2 11/16] drm/i915/ddi: initialize 128b/132b SST DP2 VFREQ registers

[Jani Nikula <jani.nikula@intel.com>]

On Tue, 31 Dec 2024, Imre Deak <imre.deak@intel.com> wrote:
> On Thu, Dec 19, 2024 at 11:34:00PM +0200, Jani Nikula wrote:
>> Write the DP2 specific VFREQ registers.
>> 
>> This is preparation for enabling 128b/132b SST. This path is not
>> reachable yet.
>> 
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_ddi.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
>> index 64528ff8856e..91e6cd91e91f 100644
>> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
>> @@ -3467,8 +3467,20 @@ static void intel_ddi_enable(struct intel_atomic_state *state,
>>  {
>>  	struct intel_display *display = to_intel_display(encoder);
>>  	struct intel_crtc *pipe_crtc;
>> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>>  	int i;
>>  
>> +	/* 128b/132b SST */
>> +	if (intel_dp_is_uhbr(crtc_state)) {
>
> Hm, not sure how this would work on HDMI (FRL), but to be sure shouldn't
> this check that crtc_state is for a DP (SST) mode?

DP MST does not call intel_ddi_enable().

Yes, it's all very subtle, and I hate the way all of the
DDI/SST/MST/etc. is intertwined, but I feel like it's overall a bigger
refactoring to clean up.

BR,
Jani.


>
>> +		const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
>> +		u64 crtc_clock_hz = KHz(adjusted_mode->crtc_clock);
>> +
>> +		intel_de_write(display, TRANS_DP2_VFREQHIGH(cpu_transcoder),
>> +			       TRANS_DP2_VFREQ_PIXEL_CLOCK(crtc_clock_hz >> 24));
>> +		intel_de_write(display, TRANS_DP2_VFREQLOW(cpu_transcoder),
>> +			       TRANS_DP2_VFREQ_PIXEL_CLOCK(crtc_clock_hz & 0xffffff));
>> +	}
>> +
>>  	intel_ddi_enable_transcoder_func(encoder, crtc_state);
>>  
>>  	/* Enable/Disable DP2.0 SDP split config before transcoder */
>> -- 
>> 2.39.5
>> 

-- 
Jani Nikula, Intel