Re: [PATCH] add transport class symlink to device object

[Matthew Wilcox]

On Sat, Aug 13, 2005 at 02:39:56PM -0700, Greg KH wrote:
> Heh, I already have a patch like this pending for 2.6.14 at:
> 	http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/gregkh-01-driver/driver-link-device-and-class.patch

Last time I tried to do something like this, it fell over with
multi-function serial ports.  Look at this example:

# ls -l /sys/class/tty/ttyS*/device | cut -c40-
/sys/class/tty/ttyS0/device -> ../../../devices/parisc/0/0:0/pci0000:00/0000:00:04.0
/sys/class/tty/ttyS1/device -> ../../../devices/parisc/0/0:0/pci0000:00/0000:00:04.0
/sys/class/tty/ttyS2/device -> ../../../devices/parisc/0/0:0/pci0000:00/0000:00:04.0
/sys/class/tty/ttyS3/device -> ../../../devices/parisc/0/0:0/pci0000:00/0000:00:05.0
/sys/class/tty/ttyS4/device -> ../../../devices/parisc/0/0:0/pci0000:00/0000:00:05.0

Adding the reverse links gets you three links in the 0000:00:04.0
directory all called 'tty' (or 'class:tty', whatever), each pointing to
a different place.  This doesn't happen for scsi devices as the class is
attached to the scsi_dev, not the pci_dev.  I think the tty subsystem
needs to be modified to add tty_devs as subdevices of the pci_dev.

-- 
"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain
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