On Wed, Oct 31, 2018 at 03:51:40PM +0000, David Howells wrote: > David Howells <dhowells@xxxxxxxxxx> wrote: > > > > > > Devices without a mac address shouldn't have a mac_dvb sysfs attribute, > > > > > I think. > > > > > > > > I'm not sure that's possible within the core infrastructure. It's a > > > > class attribute set when the class is created; I'm not sure it can be > > > > overridden on a per-device basis. > > > > > > > > Possibly the file could return "" or "none" in this case? > > > > > > That's very ugly. Have a look at, for example, rc-core wakeup filters: > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/media/rc/rc-main.c#n1844 > > > > By analogy, then, I think the thing to do is to put something like struct > > rc_dev::sysfs_groups[] into struct dvb_device (or maybe struct dvb_adapter) > > and then the dvb_mac attribute in there during dvb_register_device() based on > > whether or not the MAC address is not all zeros at that point. > > Hmmm... This is trickier than it seems. At the point the device struct is > registered, the MAC address hasn't yet been read: > > [ 13.865905] cx23885: CORE cx23885[1]: subsystem: 4254:0952, board: DVBSky S952 [card=50,autodetected] > [ 14.095559] cx25840 8-0044: cx23885 A/V decoder found @ 0x88 (cx23885[1]) > [ 14.723127] cx25840 8-0044: loaded v4l-cx23885-avcore-01.fw firmware (16382 bytes) > [ 14.738377] cx23885: cx23885_dvb_register() allocating 1 frontend(s) > [ 14.738378] cx23885: cx23885[1]: cx23885 based dvb card > [ 14.742536] i2c i2c-7: Added multiplexed i2c bus 9 > [ 15.096912] ts2020 9-0060: Montage Technology TS2022 successfully identified > [ 15.096933] dvbdev: DVB: registering new adapter (cx23885[1]) > [ 15.096936] cx23885 0000:06:00.0: DVB: registering adapter 2 frontend 0 (Montage Technology M88DS3103)... > [ 15.124665] cx23885: DVBSky S952 port 1 MAC address: 00:17:42:54:09:52 > [ 15.124666] cx23885: cx23885_dvb_register() allocating 1 frontend(s) > [ 15.124674] cx23885: cx23885[1]: cx23885 based dvb card > [ 15.128860] i2c i2c-6: Added multiplexed i2c bus 10 > [ 15.228172] ts2020 10-0060: Montage Technology TS2022 successfully identified > [ 15.228188] dvbdev: DVB: registering new adapter (cx23885[1]) > [ 15.228190] cx23885 0000:06:00.0: DVB: registering adapter 3 frontend 0 (Montage Technology M88DS3103)... > [ 15.255996] cx23885: DVBSky S952 port 2 MAC address: 00:17:42:54:09:53 > [ 15.255999] cx23885: cx23885_dev_checkrevision() Hardware revision = 0xa5 > [ 15.256004] cx23885: cx23885[1]/0: found at 0000:06:00.0, rev: 4, irq: 19, latency: 0, mmio: 0xf7a00000 > > The device structs are registered at 15.096936 and 15.228190 and this is the > point by which I think I have to set the device::groups pointer. > > However, the device isn't fully initialised at this point and the MAC address > hasn't yet been read - and so the attribute doesn't appear. proposed_mac is > set right after lines 15.124665 and 15.255996. Interestingly, a third of a > second elapses between the device registration and the MAC being printed for > each adapter. device_create() will register the device in sysfs and send uevent. So, your original udev rule/code will not work, since it always would read a mac address of 0, as proposed_mac is not populated when the device is announced. That is, unless udev is scheduled after the mac is read. I think the device_add/device_create() which triggers the uevent should be delayed until everything is available. Sean > > Any suggestions? > > David > --- > diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c > index b7171bf094fb..edbfa5549994 100644 > --- a/drivers/media/dvb-core/dvbdev.c > +++ b/drivers/media/dvb-core/dvbdev.c > @@ -450,6 +450,23 @@ static int dvb_register_media_device(struct dvb_device *dvbdev, > return 0; > } > > +static ssize_t dvb_mac_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct dvb_device *dvbdev = dev_get_drvdata(dev); > + > + return sprintf(buf, "%pM\n", dvbdev->adapter->proposed_mac); > +} > +static DEVICE_ATTR_RO(dvb_mac); > + > +static struct attribute *dvb_device_attrs[] = { > + &dev_attr_dvb_mac.attr, > + NULL > +}; > +static const struct attribute_group dvb_device_attr_grp = { > + .attrs = dvb_device_attrs, > +}; > + > int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, > const struct dvb_device *template, void *priv, > enum dvb_device_type type, int demux_sink_pads) > @@ -533,6 +550,14 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, > > mutex_unlock(&dvbdev_register_lock); > > + if (adap->proposed_mac[0] || adap->proposed_mac[1] || > + adap->proposed_mac[2] || adap->proposed_mac[3] || > + adap->proposed_mac[4] || adap->proposed_mac[5]) { is_zero_ether_addr() > + dvbdev->sysfs_groups[0] = &dvb_device_attr_grp; > + dvbdev->sysfs_groups[1] = NULL; > + adap->device->groups = dvbdev->sysfs_groups; > + } > + > clsdev = device_create(dvb_class, adap->device, > MKDEV(DVB_MAJOR, minor), > dvbdev, "dvb%d.%s%d", adap->num, dnames[type], id); > @@ -1010,6 +1035,31 @@ void dvb_module_release(struct i2c_client *client) > EXPORT_SYMBOL_GPL(dvb_module_release); > #endif > > +static ssize_t dvb_adapter_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct dvb_device *dvbdev = dev_get_drvdata(dev); > + > + return sprintf(buf, "%d\n", dvbdev->adapter->num); > +} > +static DEVICE_ATTR_RO(dvb_adapter); > + > +static ssize_t dvb_type_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct dvb_device *dvbdev = dev_get_drvdata(dev); > + > + return sprintf(buf, "%s\n", dnames[dvbdev->type]); > +} > +static DEVICE_ATTR_RO(dvb_type); > + > +static struct attribute *dvb_class_attrs[] = { > + &dev_attr_dvb_adapter.attr, > + &dev_attr_dvb_type.attr, > + NULL > +}; > +ATTRIBUTE_GROUPS(dvb_class); > + > static int dvb_uevent(struct device *dev, struct kobj_uevent_env *env) > { > struct dvb_device *dvbdev = dev_get_drvdata(dev); > @@ -1050,6 +1100,7 @@ static int __init init_dvbdev(void) > retval = PTR_ERR(dvb_class); > goto error; > } > + dvb_class->dev_groups = dvb_class_groups, > dvb_class->dev_uevent = dvb_uevent; > dvb_class->devnode = dvb_devnode; > return 0; > diff --git a/include/media/dvbdev.h b/include/media/dvbdev.h > index 881ca461b7bb..d6becdd2d56e 100644 > --- a/include/media/dvbdev.h > +++ b/include/media/dvbdev.h > @@ -127,6 +127,7 @@ struct dvb_adapter { > * > * @list_head: List head with all DVB devices > * @fops: pointer to struct file_operations > + * @sysfs_groups: Additional sysfs attributes > * @adapter: pointer to the adapter that holds this device node > * @type: type of the device, as defined by &enum dvb_device_type. > * @minor: devnode minor number. Major number is always DVB_MAJOR. > @@ -157,6 +158,7 @@ struct dvb_adapter { > struct dvb_device { > struct list_head list_head; > const struct file_operations *fops; > + const struct attribute_group *sysfs_groups[2]; > struct dvb_adapter *adapter; > enum dvb_device_type type; > int minor;
