Messages in this thread | | | Date | Tue, 26 Sep 2006 07:26:40 -0700 | From | Greg KH <> | Subject | Re: [PATCH 30/47] Driver core: create devices/virtual/ tree |
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On Tue, Sep 26, 2006 at 09:51:04AM -0400, Dmitry Torokhov wrote: > On 9/26/06, Greg KH <greg@kroah.com> wrote: > >On Tue, Sep 26, 2006 at 09:24:15AM -0400, Dmitry Torokhov wrote: > >> On 9/26/06, Greg KH <greg@kroah.com> wrote: > >> >From: Greg Kroah-Hartman <gregkh@suse.de> > >> > > >> >This change creates a devices/virtual/CLASS_NAME tree for struct devices > >> >that belong to a class, yet do not have a "real" struct device for a > >> >parent. It automatically creates the directories on the fly as needed. > >> > > >> > >> Why do you need multiple virtual devices? All parentless class devices > >> could grow from a single virtual device. > > > >They could, but it's a mess of a single directory if you do that. > >Having /sys/devices/virtual/tty/ as a place for all tty virtual device > >is nicer than /sys/devices/virtual/ as a single place for all of them > >(mem, network, tty, misc, etc.) > > > > You supposed to use classes for classification, and devices to > represent the tree so that would be /sys/class/tty/...
Yes, the symlink is still in /sys/class/tty, that hasn't gone away: $ tree /sys/class/tty/ /sys/class/tty/ |-- console -> ../../devices/virtual/tty/console |-- ptmx -> ../../devices/virtual/tty/ptmx |-- tty -> ../../devices/virtual/tty/tty |-- tty0 -> ../../devices/virtual/tty/tty0 |-- tty1 -> ../../devices/virtual/tty/tty1 |-- tty10 -> ../../devices/virtual/tty/tty10 ...
It's just that /sys/devices/virtual would look very messy otherwise: $ ls /sys/devices/virtual/ cpuid input mem misc msr net pci_bus ppp sound tty vc vtconsole
$ ls /sys/devices/virtual/*/ | wc -l 133
Also, that would mean that we could not have the name of a device associated with a class to be the same as any other device associated with any other class. In the future that might be a problem, as our namespace is only so big :)
thanks,
greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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