Re: [Intel-gfx] [PATCH 07/11] drm/edid: Use GTF2 for inferred modes

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

On Sat, 27 Aug 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> For some resaon we only use the secondary GTF curve for the
> standard timings. Use it for inferred modes as well.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c | 35 ++++++++++++++++++++++++++++++++++-
>  1 file changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 0c7cbe9b44f5..fed2bdd55c09 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3546,6 +3546,35 @@ static int drm_gtf_modes_for_range(struct drm_connector *connector,
>  	return modes;
>  }
>  
> +static int drm_gtf2_modes_for_range(struct drm_connector *connector,
> +				    const struct drm_edid *drm_edid,
> +				    const struct detailed_timing *timing)
> +{
> +	int i, modes = 0;
> +	struct drm_display_mode *newmode;
> +	struct drm_device *dev = connector->dev;
> +
> +	for (i = 0; i < ARRAY_SIZE(extra_modes); i++) {
> +		const struct minimode *m = &extra_modes[i];
> +
> +		newmode = drm_gtf2_mode(dev, drm_edid, m->w, m->h, m->r);
> +		if (!newmode)
> +			return modes;
> +
> +		drm_mode_fixup_1366x768(newmode);
> +		if (!mode_in_range(newmode, drm_edid, timing) ||
> +		    !valid_inferred_mode(connector, newmode)) {
> +			drm_mode_destroy(dev, newmode);
> +			continue;
> +		}
> +
> +		drm_mode_probed_add(connector, newmode);
> +		modes++;
> +	}
> +
> +	return modes;
> +}
> +
>  static int drm_cvt_modes_for_range(struct drm_connector *connector,
>  				   const struct drm_edid *drm_edid,
>  				   const struct detailed_timing *timing)
> @@ -3594,7 +3623,11 @@ do_inferred_modes(const struct detailed_timing *timing, void *c)
>  		return; /* GTF not defined yet */
>  
>  	switch (range->flags) {
> -	case DRM_EDID_SECONDARY_GTF_SUPPORT_FLAG: /* XXX could do more */
> +	case DRM_EDID_SECONDARY_GTF_SUPPORT_FLAG:
> +		closure->modes += drm_gtf2_modes_for_range(closure->connector,
> +							   closure->drm_edid,
> +							   timing);
> +		break;
>  	case DRM_EDID_DEFAULT_GTF_SUPPORT_FLAG:

Additionally, per spec:

* Default GTF supported if bit 0 in Feature Support Byte at address 18h = 1

* Secondary GTF supported --- requires support for Default GTF

So I guess both of these would need the edid->features &
DRM_EDID_FEATURE_DEFAULT_GTF check?

Other than that,

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



>  		closure->modes += drm_gtf_modes_for_range(closure->connector,
>  							  closure->drm_edid,

-- 
Jani Nikula, Intel Open Source Graphics Center