Re: [PATCH 2/5] drm/i915/vrr: Readout framestart_delay earlier

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 9/18/2025 2:04 AM, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> In order to pretend that ICL/TGL VRR hardware has a similar guardband
> as on ADL+ we'll need access to framestart_delay already during
> intel_vrr_get_config(). Hoist the framestart_delay to an earlier point
> to make that possible.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>


> ---
>   drivers/gpu/drm/i915/display/intel_display.c | 18 +++++++++---------
>   1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index a743d1339550..c7d85fd38890 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -3891,6 +3891,15 @@ static bool hsw_get_pipe_config(struct intel_crtc *crtc,
>   	intel_joiner_get_config(pipe_config);
>   	intel_dsc_get_config(pipe_config);
>   
> +	if (!transcoder_is_dsi(pipe_config->cpu_transcoder)) {
> +		tmp = intel_de_read(display, CHICKEN_TRANS(display, pipe_config->cpu_transcoder));
> +
> +		pipe_config->framestart_delay = REG_FIELD_GET(HSW_FRAME_START_DELAY_MASK, tmp) + 1;
> +	} else {
> +		/* no idea if this is correct */
> +		pipe_config->framestart_delay = 1;
> +	}
> +
>   	if (!transcoder_is_dsi(pipe_config->cpu_transcoder) ||
>   	    DISPLAY_VER(display) >= 11)
>   		intel_get_transcoder_timings(crtc, pipe_config);
> @@ -3942,15 +3951,6 @@ static bool hsw_get_pipe_config(struct intel_crtc *crtc,
>   		pipe_config->pixel_multiplier = 1;
>   	}
>   
> -	if (!transcoder_is_dsi(pipe_config->cpu_transcoder)) {
> -		tmp = intel_de_read(display, CHICKEN_TRANS(display, pipe_config->cpu_transcoder));
> -
> -		pipe_config->framestart_delay = REG_FIELD_GET(HSW_FRAME_START_DELAY_MASK, tmp) + 1;
> -	} else {
> -		/* no idea if this is correct */
> -		pipe_config->framestart_delay = 1;
> -	}
> -
>   out:
>   	intel_display_power_put_all_in_set(display, &crtc->hw_readout_power_domains);
>