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