[Intel-gfx] [PATCH] drm/i915/dsc: fix DSS CTL register usage for ICL DSI transcoders

[Jani Nikula]

On Fri, 19 Mar 2021, "Navare, Manasi" <manasi.d.navare at intel.com> wrote:
> On Fri, Mar 19, 2021 at 01:53:33PM +0200, Jani Nikula wrote:
>> Use the correct DSS CTL registers for ICL DSI transcoders.
>> 
>> As a side effect, this also brings back the sanity check for trying to
>> use pipe DSC registers on pipe A on ICL.
>> 
>> Fixes: 8a029c113b17 ("drm/i915/dp: Modify VDSC helpers to configure DSC for Bigjoiner slave")
>> References: http://lore.kernel.org/r/87eegxq2lq.fsf@intel.com
>
> Thanks Jani for the detailed review comments here and explanation on what
> broke the DSI DSC on < Gen 12 platforms.
>
>> Cc: Manasi Navare <manasi.d.navare at intel.com>
>> Cc: Animesh Manna <animesh.manna at intel.com>
>> Cc: Vandita Kulkarni <vandita.kulkarni at intel.com>
>> Cc: <stable at vger.kernel.org> # v5.11+
>> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
>> 
>> ---
>> 
>> Untested, I don't have the platform.
>> ---
>>  drivers/gpu/drm/i915/display/intel_vdsc.c | 10 ++--------
>>  1 file changed, 2 insertions(+), 8 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
>> index f58cc5700784..a86c57d117f2 100644
>> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
>> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
>> @@ -1014,20 +1014,14 @@ static i915_reg_t dss_ctl1_reg(const struct intel_crtc_state *crtc_state)
>>  {
>>  	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
>>  
>> -	if (crtc_state->cpu_transcoder == TRANSCODER_EDP)
>> -		return DSS_CTL1;
>> -
>> -	return ICL_PIPE_DSS_CTL1(pipe);
>> +	return is_pipe_dsc(crtc_state) ? ICL_PIPE_DSS_CTL1(pipe) : DSS_CTL1;
>
> Yes using is_pipe_dsc() makes sense here in order to select proper DSS_CTL regs
> for DSI.
>
> Reviewed-by: Manasi Navare <manasi.d.navare at intel.com>

Thanks, pushed to drm-intel-next.

BR,
Jani.

>
> Manasi
>
>>  }
>>  
>>  static i915_reg_t dss_ctl2_reg(const struct intel_crtc_state *crtc_state)
>>  {
>>  	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
>>  
>> -	if (crtc_state->cpu_transcoder == TRANSCODER_EDP)
>> -		return DSS_CTL2;
>> -
>> -	return ICL_PIPE_DSS_CTL2(pipe);
>> +	return is_pipe_dsc(crtc_state) ? ICL_PIPE_DSS_CTL2(pipe) : DSS_CTL2;
>>  }
>>  
>>  void intel_dsc_enable(struct intel_encoder *encoder,
>> -- 
>> 2.20.1
>> 
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-- 
Jani Nikula, Intel Open Source Graphics Center