[Intel-gfx] [PATCH v4 18/18] drm/i915: Fix vblank evasion with vrr

[Navare, Manasi]

On Wed, Jan 13, 2021 at 02:09:35PM -0800, Manasi Navare wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> With vrr enabled the hardware no longer latches the registers
> automagically at vblank start. The point at which it will do the
> latching even when no push has been sent is the vmax decision
> boundary. That is the thing we need to evade to avoid our
> register latching to get split between two frames.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>

Makes sense to us vmax vblank start here with vrr enable

Reviewed-by: Manasi Navare <manasi.d.navare at intel.com>

Manasi

> ---
>  drivers/gpu/drm/i915/display/intel_sprite.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
> index 0e82d1629d2d..530ce0497559 100644
> --- a/drivers/gpu/drm/i915/display/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/display/intel_sprite.c
> @@ -101,7 +101,10 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
>  	if (new_crtc_state->uapi.async_flip)
>  		return;
>  
> -	vblank_start = intel_mode_vblank_start(adjusted_mode);
> +	if (new_crtc_state->vrr.enable)
> +		vblank_start = intel_vrr_vmax_vblank_start(new_crtc_state);
> +	else
> +		vblank_start = intel_mode_vblank_start(adjusted_mode);
>  
>  	/* FIXME needs to be calibrated sensibly */
>  	min = vblank_start - intel_usecs_to_scanlines(adjusted_mode,
> -- 
> 2.19.1
>