[Intel-gfx] [PATCH] drm/dp: Add function to parse EDID descriptors for adaptive sync limits

[Manasi Navare]

On Thu, Oct 24, 2019 at 12:31:06PM +0200, Thierry Reding wrote:
> On Wed, Oct 23, 2019 at 05:00:41PM -0700, Manasi Navare wrote:
> > Adaptive Sync is a VESA feature so add a DRM core helper to parse
> > the EDID's detailed descritors to obtain the adaptive sync monitor range.
> > Store this info as part fo drm_display_info so it can be used
> > across all drivers.
> > This part of the code is stripped out of amdgpu's function
> > amdgpu_dm_update_freesync_caps() to make it generic and be used
> > across all DRM drivers
> > 
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Harry Wentland <harry.wentland at amd.com>
> > Cc: Clinton A Taylor <clinton.a.taylor at intel.com>
> > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> > ---
> >  drivers/gpu/drm/drm_edid.c  | 49 +++++++++++++++++++++++++++++++++++++
> >  include/drm/drm_connector.h | 25 +++++++++++++++++++
> >  include/drm/drm_edid.h      |  2 ++
> >  3 files changed, 76 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > index 474ac04d5600..97dd1200773e 100644
> > --- a/drivers/gpu/drm/drm_edid.c
> > +++ b/drivers/gpu/drm/drm_edid.c
> > @@ -4707,6 +4707,52 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
> >  	}
> >  }
> >  
> > +void drm_get_adaptive_sync_limits(struct drm_connector *connector,
> > +				  const struct edid *edid)
> > +{
> > +	struct drm_display_info *info = &connector->display_info;
> > +	const struct detailed_timing *timing;
> > +	const struct detailed_non_pixel *data;
> > +	const struct detailed_data_monitor_range *range;
> > +	int i;
> 
> This can be unsigned int.

Yes this can be unsigned, will change this

> 
> > +
> > +	/*
> > +	 * Restrict Adaptive Sync only for dp and edp
> > +	 */
> > +	if (connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort &&
> > +	    connector->connector_type != DRM_MODE_CONNECTOR_eDP)
> > +		return;
> > +
> > +	if (edid->version <= 1 && !(edid->version == 1 && edid->revision > 1))
> > +		return;
> > +
> > +	for (i = 0; i < 4; i++) {
> > +		timing  = &edid->detailed_timings[i];
> > +		data    = &timing->data.other_data;
> > +		range   = &data->data.range;
> > +		/*
> > +		 * Check if monitor has continuous frequency mode
> > +		 */
> > +		if (data->type != EDID_DETAIL_MONITOR_RANGE)
> > +			continue;
> > +		/*
> > +		 * Check for flag range limits only. If flag == 1 then
> > +		 * no additional timing information provided.
> > +		 * Default GTF, GTF Secondary curve and CVT are not
> > +		 * supported
> > +		 */
> > +		if (range->flags != 1)
> > +			continue;
> > +
> > +		info->adaptive_sync.min_vfreq = range->min_vfreq;
> > +		info->adaptive_sync.max_vfreq = range->max_vfreq;
> > +		info->adaptive_sync.pixel_clock_mhz =
> > +			range->pixel_clock_mhz * 10;
> > +		break;
> > +	}
> > +}
> > +EXPORT_SYMBOL(drm_get_adaptive_sync_limits);
> > +
> >  /* A connector has no EDID information, so we've got no EDID to compute quirks from. Reset
> >   * all of the values which would have been set from EDID
> >   */
> > @@ -4728,6 +4774,7 @@ drm_reset_display_info(struct drm_connector *connector)
> >  	memset(&info->hdmi, 0, sizeof(info->hdmi));
> >  
> >  	info->non_desktop = 0;
> > +	memset(&info->adaptive_sync, 0, sizeof(info->adaptive_sync));
> >  }
> >  
> >  u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edid)
> > @@ -4743,6 +4790,8 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
> >  
> >  	info->non_desktop = !!(quirks & EDID_QUIRK_NON_DESKTOP);
> >  
> > +	drm_get_adaptive_sync_limits(connector, edid);
> > +
> >  	DRM_DEBUG_KMS("non_desktop set to %d\n", info->non_desktop);
> >  
> >  	if (edid->revision < 3)
> > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> > index 5f8c3389d46f..a27a84270d8d 100644
> > --- a/include/drm/drm_connector.h
> > +++ b/include/drm/drm_connector.h
> > @@ -254,6 +254,26 @@ enum drm_panel_orientation {
> >  	DRM_MODE_PANEL_ORIENTATION_RIGHT_UP,
> >  };
> >  
> > +/**
> > + * struct drm_adaptive_sync_info - Panel's Adaptive Sync capabilities for
> > + * &drm_display_info
> > + *
> > + * This struct is used to store a Panel's Adaptive Sync capabilities
> > + * as parsed from EDID's detailed monitor range descriptor block.
> > + *
> > + * @min_vfreq: This is the min supported refresh rate in Hz from
> > + *             EDID's detailed monitor range.
> > + * @max_vfreq: This is the max supported refresh rate in Hz from
> > + *             EDID's detailed monitor range
> > + * @pixel_clock_mhz: This is the dotclock in MHz from
> > + *                   EDID's detailed monitor range
> > + */
> > +struct drm_adaptive_sync_info {
> > +	int min_vfreq;
> > +	int max_vfreq;
> > +	int pixel_clock_mhz;
> 
> Any reason why these can't be unsigned? Also, does it perhaps make sense
> to store the pixel clock as kHz like we do everywhere else?
>

Yes I could change these to unsigned as well, just kept is similar to the AMDGPU defs to begin with
Also the pixel clock in MHz is to align with the drm_edid.h in detailed_data_monitor_range

Regards
Manasi
 
> Thierry