On Wed, 18 Nov 2020 10:52:12 +0000 Simon Ser contact@emersion.fr wrote:
Document how to perform a forced probe, and when should user-space do it.
Signed-off-by: Simon Ser contact@emersion.fr Cc: Daniel Vetter daniel@ffwll.ch Cc: Pekka Paalanen ppaalanen@gmail.com
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.
Hi,
as I have no prior knowledge at all about how struct drm_mode_get_connector works, the above paragraph only confuses me. count_modes sounds totally unrelated to probing, and what does that even do in this struct at all, how does one use this thing. I only know the libdrm API for this. So I can't ack this bit.
- 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).
This paragraph is good and clear to me.
- */
struct drm_mode_get_connector {
__u64 encoders_ptr;
Thanks, pq