Re: [PATCH v5 7/9] drm/bridge_connector: hook drm_atomic_helper_connector_hdmi_update_edid()

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On Tue, Dec 03, 2024 at 04:25:58PM +0200, Jani Nikula wrote:
> On Sun, 01 Dec 2024, Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > Extend drm_bridge_connector code to read the EDID and use it to update
> > connector status if the bridge chain implements HDMI bridge. Performing
> > it from the generic location minimizes individual bridge's code and
> > enforces standard behaviour from all corresponding drivers.
> >
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/display/drm_bridge_connector.c | 67 ++++++++++++++++++++------
> >  1 file changed, 53 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
> > index 12ab9f14cc8a8672478ae2804c9a68d766d88ea5..71ae3b2c9049016d1cc0d39a787f6461633efd53 100644
> > --- a/drivers/gpu/drm/display/drm_bridge_connector.c
> > +++ b/drivers/gpu/drm/display/drm_bridge_connector.c
> > @@ -17,6 +17,7 @@
> >  #include <drm/drm_edid.h>
> >  #include <drm/drm_managed.h>
> >  #include <drm/drm_modeset_helper_vtables.h>
> > +#include <drm/drm_print.h>
> >  #include <drm/drm_probe_helper.h>
> >  #include <drm/display/drm_hdmi_state_helper.h>
> >  
> > @@ -175,17 +176,55 @@ static void drm_bridge_connector_disable_hpd(struct drm_connector *connector)
> >   * Bridge Connector Functions
> >   */
> >  
> > +static const struct drm_edid *
> > +drm_bridge_connector_read_edid(struct drm_connector *connector,
> > +			       enum drm_connector_status status)
> > +{
> > +	struct drm_bridge_connector *bridge_connector =
> > +		to_drm_bridge_connector(connector);
> > +	const struct drm_edid *drm_edid;
> > +	struct drm_bridge *bridge;
> > +
> > +	bridge = bridge_connector->bridge_edid;
> > +	if (!bridge)
> > +		return NULL;
> > +
> > +	if (status != connector_status_connected)
> > +		return NULL;
> > +
> > +	drm_edid = drm_bridge_edid_read(bridge, connector);
> > +	if (!drm_edid_valid(drm_edid)) {
> 
> What's the case this check is for?
> 
> My preference would be that bridge->funcs->edid_read() uses
> drm_edid_read*() family of functions that do the checks and return the
> EDID.
> 
> There are some cases that just allocate a blob and return it. Would be
> nice if they could be converted, but in the mean time could use
> drm_edid_valid() right there. Additional validity checks are redundant.

This was c&p from drm_bridge_connector_get_modes_edid(). If you think
that the check is redundant, could you please send a patch dropping the
check?

> 
> BR,
> Jani.
> 
> 
> > +		drm_edid_free(drm_edid);
> > +		return NULL;
> > +	}
> > +
> > +	return drm_edid;
> > +}
> > +
> >  static enum drm_connector_status
> >  drm_bridge_connector_detect(struct drm_connector *connector, bool force)
> >  {
> >  	struct drm_bridge_connector *bridge_connector =
> >  		to_drm_bridge_connector(connector);
> >  	struct drm_bridge *detect = bridge_connector->bridge_detect;
> > +	struct drm_bridge *hdmi = bridge_connector->bridge_hdmi;
> >  	enum drm_connector_status status;
> >  
> >  	if (detect) {
> >  		status = detect->funcs->detect(detect);
> >  
> > +		if (hdmi) {
> > +			const struct drm_edid *drm_edid;
> > +			int ret;
> > +
> > +			drm_edid = drm_bridge_connector_read_edid(connector, status);
> > +			ret = drm_atomic_helper_connector_hdmi_update_edid(connector, drm_edid);
> > +			if (ret)
> > +				drm_warn(connector->dev, "updating EDID failed with %d\n", ret);
> > +
> > +			drm_edid_free(drm_edid);
> > +		}
> > +
> >  		drm_bridge_connector_hpd_notify(connector, status);
> >  	} else {
> >  		switch (connector->connector_type) {
> > @@ -246,29 +285,29 @@ static const struct drm_connector_funcs drm_bridge_connector_funcs = {
> >  static int drm_bridge_connector_get_modes_edid(struct drm_connector *connector,
> >  					       struct drm_bridge *bridge)
> >  {
> > +	struct drm_bridge_connector *bridge_connector =
> > +		to_drm_bridge_connector(connector);
> > +	struct drm_bridge *hdmi = bridge_connector->bridge_hdmi;
> >  	enum drm_connector_status status;
> >  	const struct drm_edid *drm_edid;
> > -	int n;
> >  
> >  	status = drm_bridge_connector_detect(connector, false);
> >  	if (status != connector_status_connected)
> > -		goto no_edid;
> > +		return 0;
> >  
> > -	drm_edid = drm_bridge_edid_read(bridge, connector);
> > -	if (!drm_edid_valid(drm_edid)) {
> > +	/* In HDMI setup the EDID has been read and handled as a part of .detect() */
> > +	if (!hdmi) {
> > +		drm_edid = drm_bridge_connector_read_edid(connector, status);
> > +		if (!drm_edid) {
> > +			drm_edid_connector_update(connector, NULL);
> > +			return 0;
> > +		}
> > +
> > +		drm_edid_connector_update(connector, drm_edid);
> >  		drm_edid_free(drm_edid);
> > -		goto no_edid;
> >  	}
> >  
> > -	drm_edid_connector_update(connector, drm_edid);
> > -	n = drm_edid_connector_add_modes(connector);
> > -
> > -	drm_edid_free(drm_edid);
> > -	return n;
> > -
> > -no_edid:
> > -	drm_edid_connector_update(connector, NULL);
> > -	return 0;
> > +	return drm_edid_connector_add_modes(connector);
> >  }
> >  
> >  static int drm_bridge_connector_get_modes(struct drm_connector *connector)
> 
> -- 
> Jani Nikula, Intel

-- 
With best wishes
Dmitry