Document how to perform a forced probe, and when should user-space do it.
Signed-off-by: Simon Ser <contact@xxxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx>
---
include/uapi/drm/drm_mode.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 5ad10ab2a577..09647b799f39 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -368,6 +368,19 @@ enum drm_mode_subconnector {
#define DRM_MODE_CONNECTOR_WRITEBACK 18
#define DRM_MODE_CONNECTOR_SPI 19
+/**
+ * struct drm_mode_get_connector - get connector metadata
+ *
+ * If the @count_modes field is set to zero, the kernel will perform a forced
+ * probe on the connector to refresh the connector status, modes and EDID.
+ * A forced-probe can be slow and the ioctl will block.
+ *
+ * User-space shouldn't need to force-probe connectors in general: the kernel
+ * will automatically take care of probing connectors that don't support
+ * hot-plug detection when appropriate. However, user-space may force-probe
+ * connectors on user request (e.g. clicking a "Scan connectors" button, or
+ * opening a UI to manage screens).
+ */
struct drm_mode_get_connector {
__u64 encoders_ptr;
--
2.29.2
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