Re: [PATCH 2/8] drm/i915: Handle interlaced modes in intel_set_transcoder_timings_lrr()

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

On Thu, 16 Jan 2025, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> I want to start using intel_set_transcoder_timings_lrr() also for
> fixing up the vblank delay during boot. To that end make sure it
> can cope with interlaced modes as well.
>
> Note that we have soft-defeatured interlaced modes on tgl+ so
> technically this is dead code, but if we ever have the need to
> bring interlaced support back it seems better to handle this.

I might've added that as a comment in code, but *shrug*.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>


>
> Cc: Paz Zcharya <pazz@chromium.org>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 5ba3b2d658e5..1260e394afc7 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -2923,6 +2923,12 @@ static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc
>  	crtc_vblank_start = adjusted_mode->crtc_vblank_start;
>  	crtc_vblank_end = adjusted_mode->crtc_vblank_end;
>  
> +	if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE) {
> +		/* the chip adds 2 halflines automatically */
> +		crtc_vtotal -= 1;
> +		crtc_vblank_end -= 1;
> +	}
> +
>  	if (DISPLAY_VER(dev_priv) >= 13) {
>  		/*
>  		 * VBLANK_START not used by hw, just clear it
> @@ -2931,8 +2937,6 @@ static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc
>  		crtc_vblank_start = 1;
>  	}
>  
> -	drm_WARN_ON(&dev_priv->drm, adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE);
> -
>  	/*
>  	 * The hardware actually ignores TRANS_VBLANK.VBLANK_END in DP mode.
>  	 * But let's write it anyway to keep the state checker happy.

-- 
Jani Nikula, Intel