On Tue, Nov 11, 2025 at 09:13:06PM +0200, Ville Syrjälä wrote: > On Tue, Nov 11, 2025 at 08:54:59PM +0200, Ville Syrjälä wrote: > > On Tue, Nov 11, 2025 at 06:23:35PM +0200, Marius Vlad wrote: > > > Introduce 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. > > > > > > A subsequent change would make use of this connector status to propagate > > > per-connector udev hotplug events. > > > > > > The connector status is set in the drm_connector_funcs.fill_modes/vkms > > > ConfigFS connector's status and cleared out when firing out KMS uevents. > > > > > > 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. > > > > > > Signed-off-by: Marius Vlad <[email protected]> > > > --- > > > drivers/gpu/drm/drm_connector.c | 1 + > > > drivers/gpu/drm/drm_probe_helper.c | 17 +++++++++++++++++ > > > drivers/gpu/drm/drm_sysfs.c | 1 + > > > drivers/gpu/drm/vkms/vkms_configfs.c | 6 ++++++ > > > include/drm/drm_connector.h | 3 +++ > > > 5 files changed, 28 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..f0474368e98d 100644 > > > --- a/drivers/gpu/drm/drm_probe_helper.c > > > +++ b/drivers/gpu/drm/drm_probe_helper.c > > > @@ -629,6 +629,8 @@ int drm_helper_probe_single_connector_modes(struct > > > drm_connector *connector, > > > mod_delayed_work(system_wq, > > > &dev->mode_config.output_poll_work, > > > 0); > > > + > > > + connector->status_changed = true; > > > > .fill_modes() gets exectued from the getconnector() ioctl which userspace > > issues in response to the uevent. Not the other way around. So looks > > like you have the chicken and egg the wrong way around here. > > Oh, and we already have a connector->epoch_counter which is supposed > track whether anything on the connector has changed. So I'm not sure > what extra this new boolean is supposed to achieve on top of that? epoch_counter doesn't take all cases into consideration. For the instance the connector list loop in output_poll_execute will be a no-op if we try to simulate a hot-plug event with drm_sysfs. I suppose we could've have used it for (real) HW hot-plug.
There's a few use-cases:
- 2 with real HW hot-plug - one for polling and one for HPD
- 2 for with virtual connectors - one for VKMS and one for drm_sysfs
The bool helps to know -- in case you have multiple connectors -- which
of them had a hot-plug event.
>
> > > }
> > >
> > > /*
> > > @@ -732,6 +734,17 @@
> > > 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;
> > > +
> > > + mutex_lock(&dev->mode_config.mutex);
> > > + drm_connector_list_iter_begin(dev, &conn_iter);
> > > + drm_for_each_connector_iter(connector, &conn_iter) {
> > > + connector->status_changed = false;
> > > + }
> > > + drm_connector_list_iter_end(&conn_iter);
> > > + mutex_unlock(&dev->mode_config.mutex);
> > > +
> > > drm_sysfs_hotplug_event(dev);
> > > drm_client_dev_hotplug(dev);
> > > }
> > > @@ -748,6 +761,10 @@ 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/drivers/gpu/drm/vkms/vkms_configfs.c
> > > b/drivers/gpu/drm/vkms/vkms_configfs.c
> > > index 506666e21c91..6d6dd1a2c3a6 100644
> > > --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> > > +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> > > @@ -537,8 +537,14 @@ static ssize_t connector_status_store(struct
> > > config_item *item,
> > > {
> > > struct vkms_configfs_connector *connector;
> > > enum drm_connector_status status;
> > > + struct vkms_connector *vkms_connector;
> > > + struct vkms_device *vkms_dev;
> > >
> > > connector = connector_item_to_vkms_configfs_connector(item);
> > > + vkms_connector = connector->config->connector;
> > > + vkms_dev = connector->config->config->dev;
> > > + scoped_guard(mutex, &vkms_dev->drm.mode_config.mutex)
> > > + vkms_connector->base.status_changed = true;
> > >
> > > if (kstrtouint(page, 10, &status))
> > > return -EINVAL;
> > > 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
> >
> > --
> > Ville Syrjälä
> > Intel
>
> --
> Ville Syrjälä
> Intel
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