[PATCH v7 09/11] drm: uevent for connector status change

[Pekka Paalanen]

On Thu, 4 Jul 2019 16:12:10 +0530
Ramalingam C <ramalingam.c at intel.com> wrote:

> On 2019-07-04 at 14:12:27 +0300, Pekka Paalanen wrote:
> > On Tue,  7 May 2019 21:57:43 +0530
> > Ramalingam C <ramalingam.c at intel.com> wrote:
> >   
> > > DRM API for generating uevent for a status changes of connector's
> > > property.
> > > 
> > > This uevent will have following details related to the status change:
> > > 
> > >   HOTPLUG=1, CONNECTOR=<connector_id> and PROPERTY=<property_id>
> > > 
> > > Need ACK from this uevent from userspace consumer.
> > > 
> > > v2:
> > >   Minor fixes at KDoc comments [Daniel]
> > > v3:
> > >   Check the property is really attached with connector [Daniel]
> > > 
> > > Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
> > > Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> > > ---
> > >  drivers/gpu/drm/drm_sysfs.c | 35 +++++++++++++++++++++++++++++++++++
> > >  include/drm/drm_sysfs.h     |  5 ++++-
> > >  2 files changed, 39 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> > > index 18b1ac442997..63fa951a20db 100644
> > > --- a/drivers/gpu/drm/drm_sysfs.c
> > > +++ b/drivers/gpu/drm/drm_sysfs.c
> > > @@ -21,6 +21,7 @@
> > >  #include <drm/drm_sysfs.h>
> > >  #include <drm/drmP.h>
> > >  #include "drm_internal.h"
> > > +#include "drm_crtc_internal.h"
> > >  
> > >  #define to_drm_minor(d) dev_get_drvdata(d)
> > >  #define to_drm_connector(d) dev_get_drvdata(d)
> > > @@ -320,6 +321,9 @@ void drm_sysfs_lease_event(struct drm_device *dev)
> > >   * Send a uevent for the DRM device specified by @dev.  Currently we only
> > >   * set HOTPLUG=1 in the uevent environment, but this could be expanded to
> > >   * deal with other types of events.
> > > + *
> > > + * Any new uapi should be using the drm_sysfs_connector_status_event()
> > > + * for uevents on connector status change.
> > >   */
> > >  void drm_sysfs_hotplug_event(struct drm_device *dev)
> > >  {
> > > @@ -332,6 +336,37 @@ void drm_sysfs_hotplug_event(struct drm_device *dev)
> > >  }
> > >  EXPORT_SYMBOL(drm_sysfs_hotplug_event);
> > >  
> > > +/**
> > > + * drm_sysfs_connector_status_event - generate a DRM uevent for connector
> > > + * property status change
> > > + * @connector: connector on which property status changed
> > > + * @property: connector property whoes status changed.
> > > + *
> > > + * Send a uevent for the DRM device specified by @dev.  Currently we
> > > + * set HOTPLUG=1 and connector id along with the attached property id
> > > + * related to the status change.
> > > + */  
> This is the kernel doc added for drm_sysfs_connector_status_event()
> similar to drm_sysfs_hotplug_event()

Hi,

yes, it is the kernel internal doc. An UAPI doc would spell out the
attributes "CONNECTOR" and "PROPERTY" and describe their values
explaining what they are, instead of decsribing a kernel-internal
function arguments.

However, as discussed, we cannot have UAPI docs at this time, so I
guess this is the best we can have.


Thanks,
pq


> > > +void drm_sysfs_connector_status_event(struct drm_connector *connector,
> > > +				      struct drm_property *property)
> > > +{
> > > +	struct drm_device *dev = connector->dev;
> > > +	char hotplug_str[] = "HOTPLUG=1", conn_id[30], prop_id[30];
> > > +	char *envp[4] = { hotplug_str, conn_id, prop_id, NULL };
> > > +
> > > +	WARN_ON(!drm_mode_obj_find_prop_id(&connector->base,
> > > +					   property->base.id));
> > > +
> > > +	snprintf(conn_id, ARRAY_SIZE(conn_id),
> > > +		 "CONNECTOR=%u", connector->base.id);
> > > +	snprintf(prop_id, ARRAY_SIZE(prop_id),
> > > +		 "PROPERTY=%u", property->base.id);
> > > +
> > > +	DRM_DEBUG("generating connector status event\n");
> > > +
> > > +	kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
> > > +}
> > > +EXPORT_SYMBOL(drm_sysfs_connector_status_event);
> > > +
> > >  static void drm_sysfs_release(struct device *dev)
> > >  {
> > >  	kfree(dev);
> > > diff --git a/include/drm/drm_sysfs.h b/include/drm/drm_sysfs.h
> > > index 4f311e836cdc..d454ef617b2c 100644
> > > --- a/include/drm/drm_sysfs.h
> > > +++ b/include/drm/drm_sysfs.h
> > > @@ -4,10 +4,13 @@
> > >  
> > >  struct drm_device;
> > >  struct device;
> > > +struct drm_connector;
> > > +struct drm_property;
> > >  
> > >  int drm_class_device_register(struct device *dev);
> > >  void drm_class_device_unregister(struct device *dev);
> > >  
> > >  void drm_sysfs_hotplug_event(struct drm_device *dev);
> > > -
> > > +void drm_sysfs_connector_status_event(struct drm_connector *connector,
> > > +				      struct drm_property *property);
> > >  #endif  
> > 
> > Hi,
> > 
> > this patch is completely missing the UAPI documentation.
> > 
> > Weston in
> > https://gitlab.freedesktop.org/wayland/weston/merge_requests/48
> > does have good looking code to parse this event.
> > 
> > 
> > Thanks,
> > pq  
> 
> 

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