Describe what a "BAD" link-status means for user-space and how it should handle it. The logic described has been implemented in igt [1].
[1]: https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/commit/fbe61f529737191d09...
Signed-off-by: Simon Ser contact@emersion.fr Cc: Daniel Vetter daniel@ffwll.ch Cc: Manasi Navare manasi.d.navare@intel.com Cc: Pekka Paalanen ppaalanen@gmail.com --- drivers/gpu/drm/drm_connector.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index f2b20fd66319..08ba84f9787a 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -994,6 +994,12 @@ static const struct drm_prop_enum_list dp_colorspaces[] = { * after modeset, the kernel driver may set this to "BAD" and issue a * hotplug uevent. Drivers should update this value using * drm_connector_set_link_status_property(). + * + * When user-space receives the hotplug uevent and detects a "BAD" + * link-status, the connector is no longer enabled. The list of available + * modes may have changed. User-space is expected to pick a new mode if + * the current one has disappeared and perform a new modeset with + * link-status set to "GOOD" to re-enable the connector. * non_desktop: * Indicates the output should be ignored for purposes of displaying a * standard desktop environment or console. This is most likely because