Re: Flaw in the driver-model implementation of attributes

[Alan Stern]

On Mon, 16 Jun 2003, Russell King wrote:

> Have you noticed the two symlinks which are created from the class
> device.  For example:
> 
> /sysfs/class/pcmcia_socket/
> |-- pcmcia_socket0
> |   |-- device -> ../../../devices/pci0/0000:00:01.0
> |   |-- driver -> ../../../bus/pci/drivers/yenta_cardbus
> |   `-- status
> `-- pcmcia_socket1
>     |-- device -> ../../../devices/pci0/0000:00:01.1
>     |-- driver -> ../../../bus/pci/drivers/yenta_cardbus
>     `-- status
> 
> This means you can access the physical device attributes using (eg):
> 	/sysfs/class/pcmcia_socket/pcmcia_socket0/device/resource
> the driver attributes:
> 	/sysfs/class/pcmcia_socket/pcmcia_socket0/driver/...
> and the class attributes:
> 	/sysfs/class/pcmcia_socket/pcmcia_socket0/...
> 
> You don't have to try to work out where in /sys/bus and /sys/devices the
> driver and device respectively are - that's already done for you.

This doesn't provide any really good place to put device attributes that 
are owned by the driver.  They can't go in
	/sysfs/class/pcmcia_socket/pcmcia_socket0/device/...
because the driver doesn't own the device.  They can't go in
	/sysfs/class/pcmcia_socket/pcmcia_socket0/driver/...
because they aren't attributes of the _driver_, they're attributes of the 
_device_.  And they certainly aren't class attributes.

So where would you put them?  You'd have to create another subdirectory of
	/sysfs/class/pcmcia_socket/pcmcia_socket0/
owned by the driver.  No really good name for this subdirectory spings 
to mind, and it's still kind of awkward.  But doable.

Alan Stern