Re: mac80211_hwsim driver attribute

Re: mac80211_hwsim driver attribute

[Johannes Berg]

On Wed, 2013-04-03 at 13:38 +0000, Martin Pitt wrote:
> Hello John, hello Johannes,
> 
> first, many thanks for this great mac80211_hwsim module! I am
> currently working on automatic test cases for the Linux network stack
> (wpa_supplicant, dhclient, NetworkManager, etc.), and this is of great
> help.
> 
> One issue is that NetworkManager does not get along with these
> simulated interfaces:
> 
> NetworkManager[24027]: <warn> /sys/devices/virtual/mac80211_hwsim/hwsim0/net/wlan1: couldn't determine device driver; ignoring...
> 
> It calls udev_device_get_driver() on the net device (wlan0) (and
> failing that, on its parent), but that fails because hwsim doesn't
> have a driver attribute. My real intel wifi does:
> 
> lrwxrwxrwx 1 root root 0 Apr  3 06:19 /sys/class/net/wlan0/device/driver -> ../../../../bus/pci/drivers/iwlwifi
> 
> But /sys/class/net/wlan1/device/ only has the default "uevent" and
> subsystem link.
> 
> Other drivers call something like pci_register_driver() or
> usb_register(), I figure those will register the driver symlink in
> sysfs? But admittedly I'm a kernel n00b, so I'd appreciate a hint
> where to look for.
> 
> Thank you in advance!
> 
> Martin

Re: mac80211_hwsim driver attribute

[Johannes Berg]

Martin,

>  /sys/class/net/wlan0/device/driver -> ../../../../bus/pci/drivers/iwlwifi
> 
> But /sys/class/net/wlan1/device/ only has the default "uevent" and
> subsystem link.

I suspect this is because there's no real "device", and therefore no
real driver.

We do play with device_create() in hwsim, which was likely intended to
address something like this, but I have no idea how this should really
work.

johannes

Re: mac80211_hwsim driver attribute

[Martin Pitt]

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Hello Johannes,

Johannes Berg [2013-04-03 15:44 +0200]:
> Martin,
> 
> >  /sys/class/net/wlan0/device/driver -> ../../../../bus/pci/drivers/iwlwifi
> > 
> > But /sys/class/net/wlan1/device/ only has the default "uevent" and
> > subsystem link.
> 
> I suspect this is because there's no real "device", and therefore no
> real driver.

There are real devices (wlan0, wlan1, etc.); there is also a real
driver (mac80211_hwsim), the only thing that's a bit tricky is that
there is no real bus. My impression is that such devices might belong
to /sys/bus/platform/ ?

> We do play with device_create() in hwsim, which was likely intended to
> address something like this, but I have no idea how this should really
> work.

I figured it out, it works well now. I'll send the patch to the
lists/maintainers, and CC: Dan and you.

Thanks,

Martin
-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)

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