On Tue, Sep 23, 2025 at 11:36:35AM +0300, Marius Vlad wrote:
> This patch introduces a new boolean variable used to track connector's
> connect/disconnect status and it is being used on both polling and
> the HPD (Hot Plug Detect) paths.
Please see Documentation/process/submitting-patches.rst, it has special
paragraph about "This patch".
>
> A subsequent patch would make use of this connector status to propagate
> per-connector udev hot plug events. This allows user-space to receive
> the connector's ID, rather than having a generic hot-plug event for all
> connectors, or in the HPD path, just the first one found with a
> connection status change.
It's not clear from the commit message, what is the expected behaviour.
The flag has to be set when we've detected the status change - e.g.
monitor being plugged or unplugged. When is it expected to be cleared?
>
> Signed-off-by: Marius Vlad <marius.v...@collabora.com>
> ---
> drivers/gpu/drm/drm_connector.c | 1 +
> drivers/gpu/drm/drm_probe_helper.c | 18 ++++++++++++++++++
> drivers/gpu/drm/drm_sysfs.c | 1 +
> include/drm/drm_connector.h | 3 +++
> 4 files changed, 23 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 272d6254ea47..3c6628ee3096 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -274,6 +274,7 @@ static int drm_connector_init_only(struct drm_device *dev,
>
> /* provide ddc symlink in sysfs */
> connector->ddc = ddc;
> + connector->status_changed = false;
>
> INIT_LIST_HEAD(&connector->head);
> INIT_LIST_HEAD(&connector->global_connector_list_entry);
> diff --git a/drivers/gpu/drm/drm_probe_helper.c
> b/drivers/gpu/drm/drm_probe_helper.c
> index 09b12c30df69..a865d5aa6f73 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -629,6 +629,9 @@ int drm_helper_probe_single_connector_modes(struct
> drm_connector *connector,
> mod_delayed_work(system_wq,
> &dev->mode_config.output_poll_work,
> 0);
> + mutex_lock(&dev->mode_config.mutex);
> + connector->status_changed = true;
> + mutex_unlock(&dev->mode_config.mutex);
> }
>
> /*
> @@ -732,6 +735,17 @@ EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
> */
> void drm_kms_helper_hotplug_event(struct drm_device *dev)
> {
> + struct drm_connector *connector;
> + struct drm_connector_list_iter conn_iter;
> +
> + drm_connector_list_iter_begin(dev, &conn_iter);
> + drm_for_each_connector_iter(connector, &conn_iter) {
> + mutex_lock(&dev->mode_config.mutex);
> + connector->status_changed = false;
> + mutex_unlock(&dev->mode_config.mutex);
> + }
> + drm_connector_list_iter_end(&conn_iter);
> +
> drm_sysfs_hotplug_event(dev);
> drm_client_dev_hotplug(dev);
> }
> @@ -748,6 +762,10 @@ void drm_kms_helper_connector_hotplug_event(struct
> drm_connector *connector)
> {
> struct drm_device *dev = connector->dev;
>
> + mutex_lock(&dev->mode_config.mutex);
> + connector->status_changed = false;
> + mutex_unlock(&dev->mode_config.mutex);
> +
> drm_sysfs_connector_hotplug_event(connector);
> drm_client_dev_hotplug(dev);
> }
> diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> index b01ffa4d6509..bd9161490116 100644
> --- a/drivers/gpu/drm/drm_sysfs.c
> +++ b/drivers/gpu/drm/drm_sysfs.c
> @@ -199,6 +199,7 @@ static ssize_t status_store(struct device *device,
> return ret;
>
> old_force = connector->force;
> + connector->status_changed = true;
>
> if (sysfs_streq(buf, "detect"))
> connector->force = 0;
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 8f34f4b8183d..e4310df3d55c 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -2146,6 +2146,9 @@ struct drm_connector {
> /** @force: a DRM_FORCE_<foo> state for forced mode sets */
> enum drm_connector_force force;
>
> + /** @status_changed: if the old status doesn't match current connection
> status */
> + bool status_changed;
> +
> /**
> * @edid_override: Override EDID set via debugfs.
> *
> --
> 2.47.2
>
--
With best wishes
Dmitry
