Re: [PATCH v3 02/19] drm/amd/display: Refactor amdgpu_dm_update_freesync_caps()

["Tomasz Pakuła" <tomasz.pakula.oficjalny@gmail.com>]

On Fri, 2026-02-06 at 13:22 -0500, Harry Wentland wrote:
> 
> On 2026-02-03 13:56, Tomasz Pakuła wrote:
> > [Why]
> > This function started to get very messy and hard to follow.
> > 
> > [How]
> > Eject some functionality to separate functions and simplify greatly.
> > 
> > Changes in v3:
> > - Less struct traversal in helper functions
> > 
> > Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
> > ---
> >  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 123 +++++++++++-------
> >  1 file changed, 73 insertions(+), 50 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > index 29e4a047b455..2c5877ed5f32 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > @@ -13119,8 +13119,8 @@ static void parse_edid_displayid_vrr(struct drm_connector *connector,
> >  	}
> >  }
> >  
> > -static int parse_amd_vsdb(struct amdgpu_dm_connector *aconnector,
> > -			  const struct edid *edid, struct amdgpu_hdmi_vsdb_info *vsdb_info)
> > +static int parse_amd_vsdb_did(struct amdgpu_dm_connector *aconnector,
> > +			      const struct edid *edid, struct amdgpu_hdmi_vsdb_info *vsdb_info)
> >  {
> >  	u8 *edid_ext = NULL;
> >  	int i;
> > @@ -13172,13 +13172,13 @@ static int parse_amd_vsdb(struct amdgpu_dm_connector *aconnector,
> >  	return false;
> >  }
> >  
> > -static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector,
> > -			       const struct edid *edid,
> > -			       struct amdgpu_hdmi_vsdb_info *vsdb_info)
> > +static int parse_amd_vsdb_cea(struct amdgpu_dm_connector *aconnector,
> > +			      const struct edid *edid,
> > +			      struct amdgpu_hdmi_vsdb_info *vsdb_info)
> >  {
> > +	struct amdgpu_hdmi_vsdb_info vsdb_local = {0};
> >  	u8 *edid_ext = NULL;
> >  	int i;
> > -	bool valid_vsdb_found = false;
> >  
> >  	/*----- drm_find_cea_extension() -----*/
> >  	/* No EDID or EDID extensions */
> > @@ -13199,9 +13199,47 @@ static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector,
> >  	if (edid_ext[0] != CEA_EXT)
> >  		return -ENODEV;
> >  
> > -	valid_vsdb_found = parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info);
> > +	if (!parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, &vsdb_local))
> > +		return -ENODEV;
> >  
> > -	return valid_vsdb_found ? i : -ENODEV;
> > +	*vsdb_info = vsdb_local;
> > +	return i;
> > +}
> > +
> > +static bool is_monitor_range_invalid(const struct drm_connector *conn)
> > +{
> > +	return conn->display_info.monitor_range.min_vfreq == 0 ||
> > +	       conn->display_info.monitor_range.max_vfreq == 0;
> > +}
> > +
> > +/*
> > + * Returns true if (max_vfreq - min_vfreq) > 10
> > + */
> > +static bool is_freesync_capable(const struct drm_monitor_range_info *range)
> > +{
> > +	return (range->max_vfreq - range->min_vfreq) > 10;
> > +}
> > +
> > +static void monitor_range_from_vsdb(struct drm_display_info *display,
> > +				    const struct amdgpu_hdmi_vsdb_info *vsdb)
> > +{
> > +	display->monitor_range.min_vfreq = vsdb->min_refresh_rate_hz;
> > +	display->monitor_range.max_vfreq = vsdb->max_refresh_rate_hz;
> > +}
> > +
> > +/*
> > + * Returns true if connector is capable of freesync
> > + * Optionally, can fetch the range from AMD vsdb
> > + */
> > +static bool copy_range_to_amdgpu_connector(struct drm_connector *conn)
> > +{
> > +	struct amdgpu_dm_connector *aconn = to_amdgpu_dm_connector(conn);
> > +	struct drm_monitor_range_info *range = &conn->display_info.monitor_range;
> > +
> > +	aconn->min_vfreq = range->min_vfreq;
> > +	aconn->max_vfreq = range->max_vfreq;
> > +
> > +	return is_freesync_capable(range);
> >  }
> >  
> >  /**
> > @@ -13218,13 +13256,14 @@ static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector,
> >  void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
> >  				    const struct drm_edid *drm_edid)
> >  {
> > -	int i = 0;
> >  	struct amdgpu_dm_connector *amdgpu_dm_connector =
> >  			to_amdgpu_dm_connector(connector);
> >  	struct dm_connector_state *dm_con_state = NULL;
> >  	struct dc_sink *sink;
> >  	struct amdgpu_device *adev = drm_to_adev(connector->dev);
> >  	struct amdgpu_hdmi_vsdb_info vsdb_info = {0};
> > +	struct amdgpu_hdmi_vsdb_info vsdb_did = {0};
> > +	struct dpcd_caps dpcd_caps = {0};
> >  	const struct edid *edid;
> >  	bool freesync_capable = false;
> >  	enum adaptive_sync_type as_type = ADAPTIVE_SYNC_TYPE_NONE;
> > @@ -13256,62 +13295,46 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
> >  		goto update;
> >  
> >  	edid = drm_edid_raw(drm_edid); // FIXME: Get rid of drm_edid_raw()
> > +	parse_amd_vsdb_cea(amdgpu_dm_connector, edid, &vsdb_info);
> 
> This change says it's a refactor, which in my book should
> never include a (subtle) functional change. But we're now
> calling this function for all sink_signal types, whereas
> before it was only called for HDMI_TYPE_A.

Got it. I'll explain it better in the next version. I think the edid
check was there only to guard against parsing it in parse_amd_vsdb(). I
must say the code there was not the clearest but I can't think of a
reason to check for edid in case of DP. If it's missing, the
display_info won't have a valid range.

The parsing functions check for edid as well so this check is actually
redundant and could be entirely removed. vsdb structs are initialized to
0 either way so nothing will break and nothing will get enabled by
mistake.

Quite honestly, looking at (before changes) parse_edid_displayid_vrr(),
parse_amd_vsdb(), parse_hdmi_amd_vsdb() there's quite a bit of code
duplication and especially the former two are almost the same.

> > +
> > +	if (amdgpu_dm_connector->dc_link)
> > +		dpcd_caps = amdgpu_dm_connector->dc_link->dpcd_caps;
> >  
> >  	/* Some eDP panels only have the refresh rate range info in DisplayID */
> > -	if ((connector->display_info.monitor_range.min_vfreq == 0 ||
> > -	     connector->display_info.monitor_range.max_vfreq == 0))
> > +	if (is_monitor_range_invalid(connector))
> >  		parse_edid_displayid_vrr(connector, edid);
> >  
> > -	if (edid && (sink->sink_signal == SIGNAL_TYPE_DISPLAY_PORT ||
> > -		     sink->sink_signal == SIGNAL_TYPE_EDP)) {
> > -		if (amdgpu_dm_connector->dc_link &&
> > -		    amdgpu_dm_connector->dc_link->dpcd_caps.allow_invalid_MSA_timing_param) {
> > -			amdgpu_dm_connector->min_vfreq = connector->display_info.monitor_range.min_vfreq;
> > -			amdgpu_dm_connector->max_vfreq = connector->display_info.monitor_range.max_vfreq;
> > -			if (amdgpu_dm_connector->max_vfreq - amdgpu_dm_connector->min_vfreq > 10)
> > -				freesync_capable = true;
> > -		}
> > +	if (sink->sink_signal == SIGNAL_TYPE_DISPLAY_PORT ||
> > +	    sink->sink_signal == SIGNAL_TYPE_EDP) {
> >  
> > -		parse_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);
> > +		if (dpcd_caps.allow_invalid_MSA_timing_param)
> > +			freesync_capable = copy_range_to_amdgpu_connector(connector);
> >  
> > -		if (vsdb_info.replay_mode) {
> > -			amdgpu_dm_connector->vsdb_info.replay_mode = vsdb_info.replay_mode;
> > -			amdgpu_dm_connector->vsdb_info.amd_vsdb_version = vsdb_info.amd_vsdb_version;
> > +		/* eDP */
> > +		if (edid)
> 
> Same here, I'm not entirely sure whether moving the edid
> check down here won't have a subtle behavior change.
> 
> I'd like to be either convinced that these things cannot
> change behavior, or I'd like to see this broken out into
> two patches, (1) a true refactor patch, without possible
> behavior changes, and (2) another patch that might affect
> behavior.

Will do. Now that I'm looking at this with a clear head, it's too much
in one go even for me :) I think this will end up as 3-4 patches to
clean up the vsdb parsing functions as well.

> 
> Overall I'm in favor of the changes and thank you for
> cleaning this up. I'm just worried about subtle bugs.
> 
> Harry
> 
> > +			parse_amd_vsdb_did(amdgpu_dm_connector, edid, &vsdb_did);
> > +
> > +		if (vsdb_did.replay_mode) {
> > +			amdgpu_dm_connector->vsdb_info.replay_mode = vsdb_did.replay_mode;
> > +			amdgpu_dm_connector->vsdb_info.amd_vsdb_version = vsdb_did.amd_vsdb_version;
> >  			amdgpu_dm_connector->as_type = ADAPTIVE_SYNC_TYPE_EDP;
> >  		}
> >  
> > -	} else if (drm_edid && sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) {
> > -		i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);
> > -		if (i >= 0 && vsdb_info.freesync_supported) {
> > -			amdgpu_dm_connector->min_vfreq = vsdb_info.min_refresh_rate_hz;
> > -			amdgpu_dm_connector->max_vfreq = vsdb_info.max_refresh_rate_hz;
> > -			if (amdgpu_dm_connector->max_vfreq - amdgpu_dm_connector->min_vfreq > 10)
> > -				freesync_capable = true;
> > -
> > -			connector->display_info.monitor_range.min_vfreq = vsdb_info.min_refresh_rate_hz;
> > -			connector->display_info.monitor_range.max_vfreq = vsdb_info.max_refresh_rate_hz;
> > -		}
> > +	} else if (sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A && vsdb_info.freesync_supported) {
> > +		monitor_range_from_vsdb(&connector->display_info, &vsdb_info);
> > +		freesync_capable = copy_range_to_amdgpu_connector(connector);
> >  	}
> >  
> >  	if (amdgpu_dm_connector->dc_link)
> >  		as_type = dm_get_adaptive_sync_support_type(amdgpu_dm_connector->dc_link);
> >  
> > -	if (as_type == FREESYNC_TYPE_PCON_IN_WHITELIST) {
> > -		i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);
> > -		if (i >= 0 && vsdb_info.freesync_supported && vsdb_info.amd_vsdb_version > 0) {
> > +	if (as_type == FREESYNC_TYPE_PCON_IN_WHITELIST && vsdb_info.freesync_supported) {
> > +		amdgpu_dm_connector->pack_sdp_v1_3 = true;
> > +		amdgpu_dm_connector->as_type = as_type;
> > +		amdgpu_dm_connector->vsdb_info = vsdb_info;
> >  
> > -			amdgpu_dm_connector->pack_sdp_v1_3 = true;
> > -			amdgpu_dm_connector->as_type = as_type;
> > -			amdgpu_dm_connector->vsdb_info = vsdb_info;
> > -
> > -			amdgpu_dm_connector->min_vfreq = vsdb_info.min_refresh_rate_hz;
> > -			amdgpu_dm_connector->max_vfreq = vsdb_info.max_refresh_rate_hz;
> > -			if (amdgpu_dm_connector->max_vfreq - amdgpu_dm_connector->min_vfreq > 10)
> > -				freesync_capable = true;
> > -
> > -			connector->display_info.monitor_range.min_vfreq = vsdb_info.min_refresh_rate_hz;
> > -			connector->display_info.monitor_range.max_vfreq = vsdb_info.max_refresh_rate_hz;
> > -		}
> > +		monitor_range_from_vsdb(&connector->display_info, &vsdb_info);
> > +		freesync_capable = copy_range_to_amdgpu_connector(connector);
> >  	}
> >  
> >  update:
>