diff options
Diffstat (limited to 'drivers/gpu/drm/drm_connector.c')
| -rw-r--r-- | drivers/gpu/drm/drm_connector.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index d877ddc6dc57..b7bd46033807 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -953,8 +953,7 @@ static const struct drm_prop_enum_list dp_colorspaces[] = { * connector is linked to. Drivers should never set this property directly, * it is handled by the DRM core by calling the &drm_connector_funcs.dpms * callback. For atomic drivers the remapping to the "ACTIVE" property is - * implemented in the DRM core. This is the only standard connector - * property that userspace can change. + * implemented in the DRM core. * * Note that this property cannot be set through the MODE_ATOMIC ioctl, * userspace must use "ACTIVE" on the CRTC instead. @@ -1000,6 +999,32 @@ 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 sink doesn't receive pixels anymore (e.g. the screen + * becomes completely black). 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. + * + * If multiple connectors share the same CRTC and one of them gets a "BAD" + * link-status, the other are unaffected (ie. the sinks still continue to + * receive pixels). + * + * When user-space performs an atomic commit on a connector with a "BAD" + * link-status without resetting the property to "GOOD", the sink may + * still not receive pixels. When user-space performs an atomic commit + * which resets the link-status property to "GOOD" without the + * ALLOW_MODESET flag set, it might fail because a modeset is required. + * + * User-space can only change link-status to "GOOD", changing it to "BAD" + * is a no-op. + * + * For backwards compatibility with non-atomic userspace the kernel + * tries to automatically set the link-status back to "GOOD" in the + * SETCRTC IOCTL. This might fail if the mode is no longer valid, similar + * to how it might fail if a different screen has been connected in the + * interim. * non_desktop: * Indicates the output should be ignored for purposes of displaying a * standard desktop environment or console. This is most likely because |