[PATCH] drm/i915/display: Avoid touching interlace mode registers

[Ville Syrjälä]

On Wed, Apr 16, 2025 at 10:23:07AM +0530, Shekhar Chauhan wrote:
> Commit f71c9b7bc35f("drm/i915/display: Prune Interlace modes for Display >=12")
> defeatures interlace modes starting with display version 12. However,
> there are some paths in the driver that still touch interlace-related
> registers/fields for display version >= 12. So, avoid touching those
> registers/fields.

The registers are still there.

> 
> Signed-off-by: Shekhar Chauhan <shekhar.chauhan at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 3afb85fe8536..73b1fdf0b0ff 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -2686,7 +2686,7 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  		crtc_vblank_start = 1;
>  	}
>  
> -	if (DISPLAY_VER(display) >= 4)
> +	if (DISPLAY_VER(display) >= 4 && DISPLAY_VER(display) < 12)
>  		intel_de_write(display,
>  			       TRANS_VSYNCSHIFT(display, cpu_transcoder),
>  			       vsyncshift);
> @@ -2790,7 +2790,7 @@ static bool intel_pipe_is_interlaced(const struct intel_crtc_state *crtc_state)
>  	struct intel_display *display = to_intel_display(crtc_state);
>  	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>  
> -	if (DISPLAY_VER(display) == 2)
> +	if (DISPLAY_VER(display) == 2 || DISPLAY_VER(display) >= 12)
>  		return false;
>  
>  	if (DISPLAY_VER(display) >= 9 ||
> @@ -3164,10 +3164,12 @@ static void hsw_set_transconf(const struct intel_crtc_state *crtc_state)
>  	if (display->platform.haswell && crtc_state->dither)
>  		val |= TRANSCONF_DITHER_EN | TRANSCONF_DITHER_TYPE_SP;
>  
> -	if (crtc_state->hw.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE)
> -		val |= TRANSCONF_INTERLACE_IF_ID_ILK;
> -	else
> -		val |= TRANSCONF_INTERLACE_PF_PD_ILK;
> +	if (DISPLAY_VER(display) < 12) {
> +		if (crtc_state->hw.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE)
> +			val |= TRANSCONF_INTERLACE_IF_ID_ILK;
> +		else
> +			val |= TRANSCONF_INTERLACE_PF_PD_ILK;
> +	}
>  
>  	if (display->platform.haswell &&
>  	    crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB)
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel