| Message ID | 20190613184335.7970-2-ville.syrjala@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: PATH prop for all connectors? | expand |
On Thu, 13 Jun 2019 21:43:34 +0300 Ville Syrjala <ville.syrjala@linux.intel.com> wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > The PATH blob is already being parsed by userspace for MST connectors > so the layout of the blob is now uabi. Let's document what it should > look like. > > Also add a clear note saying non-MST connectors can have a PATH prop > too. > > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: Pekka Paalanen <ppaalanen@gmail.com> > Cc: Ilia Mirkin <imirkin@alum.mit.edu> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/drm_connector.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index e17586aaa80f..ce3926e9ad11 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -899,7 +899,16 @@ static const struct drm_prop_enum_list hdmi_colorspaces[] = { > * connected. Used by DP MST. This should be set by calling > * drm_connector_set_path_property(), in the case of DP MST with the > * path property the MST manager created. Userspace cannot change this > - * property. > + * property. The value must be an ASCII string. > + * > + * For DP MST connectors the path string follows the pattern > + * "mst:<base connector ID>[-<mst port>]...", where the base connector ID > + * identifies the DP connector on the source device, and the mst ports > + * are the port numbers in the DP MST topology. Hi, what exactly is the connector ID as already used here for MST? Is it not persistent? I assume the MST port numbers are persistent as long as the physical topology does not change. > + * > + * For non-DP MST connectors the format is freeform, as long as it > + * uniquely identifies the physical path, remains stable across > + * kernel releases, and does not start with "mst:". Maybe the requirements for "persistent name" should be clarified more: - remains stable across kernel releases - is immune to driver loading/initialisation order changes - is immune to adding or removing other hardware (e.g. graphics cards) Maybe also some explicit words about what to do with dynamic non-MST connectors? Thanks, pq
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index e17586aaa80f..ce3926e9ad11 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -899,7 +899,16 @@ static const struct drm_prop_enum_list hdmi_colorspaces[] = { * connected. Used by DP MST. This should be set by calling * drm_connector_set_path_property(), in the case of DP MST with the * path property the MST manager created. Userspace cannot change this - * property. + * property. The value must be an ASCII string. + * + * For DP MST connectors the path string follows the pattern + * "mst:<base connector ID>[-<mst port>]...", where the base connector ID + * identifies the DP connector on the source device, and the mst ports + * are the port numbers in the DP MST topology. + * + * For non-DP MST connectors the format is freeform, as long as it + * uniquely identifies the physical path, remains stable across + * kernel releases, and does not start with "mst:". * TILE: * Connector tile group property to indicate how a set of DRM connector * compose together into one logical screen. This is used by both high-res @@ -1678,7 +1687,7 @@ int drm_mode_create_suggested_offset_properties(struct drm_device *dev) EXPORT_SYMBOL(drm_mode_create_suggested_offset_properties); /** - * drm_connector_set_path_property - set tile property on connector + * drm_connector_set_path_property - set path property on connector * @connector: connector to set property on. * @path: path to use for property; must not be NULL. *