From: Leo Li <sunpeng.li@xxxxxxx>
This can be used to create more descriptive symlinks for MST aux
devices. Consider the following udev rule:
SUBSYSTEM=="drm_dp_aux_dev", SUBSYSTEMS=="drm", ATTRS{mstpath}=="?*",
SYMLINK+="drm_dp_aux/by-path/$attr{mstpath}"
The following symlinks will be created (depending on your MST topology):
$ ls /dev/drm_dp_aux/by-path/
card0-mst:0-1 card0-mst:0-1-1 card0-mst:0-1-8 card0-mst:0-8
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Lyude Paul <lyude@xxxxxxxxxx>
Signed-off-by: Leo Li <sunpeng.li@xxxxxxx>
---
drivers/gpu/drm/drm_sysfs.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index ecb7b33..e000e0c 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -229,16 +229,39 @@ static ssize_t modes_show(struct device *device,
return written;
}
+static ssize_t mstpath_show(struct device *device,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct drm_connector *connector = to_drm_connector(device);
+ ssize_t ret = 0;
+ char *path;
+
+ mutex_lock(&connector->dev->mode_config.mutex);
+ if (!connector->path_blob_ptr)
+ goto unlock;
+
+ path = connector->path_blob_ptr->data;
+ ret = snprintf(buf, PAGE_SIZE, "card%d-%s\n",
+ connector->dev->primary->index, path);
+
+unlock:
+ mutex_unlock(&connector->dev->mode_config.mutex);
+ return ret;
+}
+
static DEVICE_ATTR_RW(status);
static DEVICE_ATTR_RO(enabled);
static DEVICE_ATTR_RO(dpms);
static DEVICE_ATTR_RO(modes);
+static DEVICE_ATTR_RO(mstpath);
static struct attribute *connector_dev_attrs[] = {
&dev_attr_status.attr,
&dev_attr_enabled.attr,
&dev_attr_dpms.attr,
&dev_attr_modes.attr,
+ &dev_attr_mstpath.attr,
NULL
};
--
2.7.4
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