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

[Navare, Manasi]

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>

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
>