Re: [Intel-gfx] [PATCH] drm/i915: Allow more varied alternate fixed modes for panels

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

On Wed, 31 Aug 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> On some systems the panel reports alternate modes with
> different blanking periods. If the EDID reports them and VBT
> doesn't tell us otherwise then I can't really see why they
> should be rejected. So allow their use for the purposes of
> static DRRS.
>
> For seamless DRRS we still require a much more exact match
> of course. But that logic only kicks in when selecting the
> downclock mode (or in the future when determining whether
> we can do a seamless refresh rate change due to a user
> modeset).
>
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6374
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

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

> ---
>  drivers/gpu/drm/i915/display/intel_panel.c | 25 ++++++----------------
>  1 file changed, 6 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index 237a40623dd7..cb44984bb9a2 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -81,15 +81,14 @@ static bool is_alt_drrs_mode(const struct drm_display_mode *mode,
>  		mode->clock != preferred_mode->clock;
>  }
>  
> -static bool is_alt_vrr_mode(const struct drm_display_mode *mode,
> -			    const struct drm_display_mode *preferred_mode)
> +static bool is_alt_fixed_mode(const struct drm_display_mode *mode,
> +			      const struct drm_display_mode *preferred_mode)
>  {
>  	return drm_mode_match(mode, preferred_mode,
>  			      DRM_MODE_MATCH_FLAGS |
>  			      DRM_MODE_MATCH_3D_FLAGS) &&
>  		mode->hdisplay == preferred_mode->hdisplay &&
> -		mode->vdisplay == preferred_mode->vdisplay &&
> -		mode->clock != preferred_mode->clock;
> +		mode->vdisplay == preferred_mode->vdisplay;
>  }
>  
>  const struct drm_display_mode *
> @@ -172,19 +171,7 @@ int intel_panel_compute_config(struct intel_connector *connector,
>  	return 0;
>  }
>  
> -static bool is_alt_fixed_mode(const struct drm_display_mode *mode,
> -			      const struct drm_display_mode *preferred_mode,
> -			      bool has_vrr)
> -{
> -	/* is_alt_drrs_mode() is a subset of is_alt_vrr_mode() */
> -	if (has_vrr)
> -		return is_alt_vrr_mode(mode, preferred_mode);
> -	else
> -		return is_alt_drrs_mode(mode, preferred_mode);
> -}
> -
> -static void intel_panel_add_edid_alt_fixed_modes(struct intel_connector *connector,
> -						 bool has_vrr)
> +static void intel_panel_add_edid_alt_fixed_modes(struct intel_connector *connector)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  	const struct drm_display_mode *preferred_mode =
> @@ -192,7 +179,7 @@ static void intel_panel_add_edid_alt_fixed_modes(struct intel_connector *connect
>  	struct drm_display_mode *mode, *next;
>  
>  	list_for_each_entry_safe(mode, next, &connector->base.probed_modes, head) {
> -		if (!is_alt_fixed_mode(mode, preferred_mode, has_vrr))
> +		if (!is_alt_fixed_mode(mode, preferred_mode))
>  			continue;
>  
>  		drm_dbg_kms(&dev_priv->drm,
> @@ -255,7 +242,7 @@ void intel_panel_add_edid_fixed_modes(struct intel_connector *connector,
>  {
>  	intel_panel_add_edid_preferred_mode(connector);
>  	if (intel_panel_preferred_fixed_mode(connector) && (has_drrs || has_vrr))
> -		intel_panel_add_edid_alt_fixed_modes(connector, has_vrr);
> +		intel_panel_add_edid_alt_fixed_modes(connector);
>  	intel_panel_destroy_probed_modes(connector);
>  }

-- 
Jani Nikula, Intel Open Source Graphics Center