Re: No more "device" symlinks for classes
On 1/14/07, Greg KH <[EMAIL PROTECTED]> wrote:
On Sun, Jan 14, 2007 at 09:10:59AM +0300, Andrey Borzenkov wrote:
> Pierre Ossman wrote:
>
> > Hi guys,
> >
> > I just wanted to know the rationale behind
> > 99ef3ef8d5f2f5b5312627127ad63df27c0d0d05 (no more "device" symlink in
> > class devices). I thought that was a rather convenient way of finding
> > which physical device the class device was coupled to.
> >
>
> Actually I wonder why those links still present even when I told system not
> to create them?
>
> {pts/1}% grep DEPRE /boot/config
> # CONFIG_SYSFS_DEPRECATED is not set
> # CONFIG_PM_SYSFS_DEPRECATED is not set
> {pts/1}% find /sys/class -name device
> /sys/class/pcmcia_socket/pcmcia_socket2/device
> /sys/class/pcmcia_socket/pcmcia_socket1/device
> /sys/class/pcmcia_socket/pcmcia_socket0/device
> /sys/class/usb_device/usbdev1.1/device
> /sys/class/usb_host/usb_host1/device
> /sys/class/scsi_disk/0:0:0:0/device
> /sys/class/scsi_device/1:0:0:0/device
> /sys/class/scsi_device/0:0:0:0/device
> /sys/class/scsi_host/host1/device
> /sys/class/scsi_host/host0/device
> /sys/class/net/eth0/device
> /sys/class/net/eth1/device
> /sys/class/input/input1/ts0/device
> /sys/class/input/input1/mouse0/device
> /sys/class/input/input1/event1/device
> /sys/class/input/input1/device
> /sys/class/input/input0/event0/device
> /sys/class/input/input0/device
> {pts/1}% uname -a
> Linux cooker 2.6.20-rc5-1avb #10 Sat Jan 13 14:05:34 MSK 2007 i686 Pentium
> III (Coppermine) GNU/Linux
Because I haven't finished converting all of the different usages of
struct class_device to struct device just yet. When that happens, those
links go away, as the /sys/class/foo_class/foo is a symlink itself into
the /sys/devices/ tree.
Right, you only told not to create the links for already converted
subsystems to create the class-devices in /sys/devices. You can never
supress the links for subsystems which still create device-directories
in /sys/class, because you would lose the parent information then and
udev and HAL couldn't work anymore.
Kay
Kay
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Re: No more "device" symlinks for classes
On Sun, Jan 14, 2007 at 09:10:59AM +0300, Andrey Borzenkov wrote:
> Pierre Ossman wrote:
>
> > Hi guys,
> >
> > I just wanted to know the rationale behind
> > 99ef3ef8d5f2f5b5312627127ad63df27c0d0d05 (no more "device" symlink in
> > class devices). I thought that was a rather convenient way of finding
> > which physical device the class device was coupled to.
> >
>
> Actually I wonder why those links still present even when I told system not
> to create them?
>
> {pts/1}% grep DEPRE /boot/config
> # CONFIG_SYSFS_DEPRECATED is not set
> # CONFIG_PM_SYSFS_DEPRECATED is not set
> {pts/1}% find /sys/class -name device
> /sys/class/pcmcia_socket/pcmcia_socket2/device
> /sys/class/pcmcia_socket/pcmcia_socket1/device
> /sys/class/pcmcia_socket/pcmcia_socket0/device
> /sys/class/usb_device/usbdev1.1/device
> /sys/class/usb_host/usb_host1/device
> /sys/class/scsi_disk/0:0:0:0/device
> /sys/class/scsi_device/1:0:0:0/device
> /sys/class/scsi_device/0:0:0:0/device
> /sys/class/scsi_host/host1/device
> /sys/class/scsi_host/host0/device
> /sys/class/net/eth0/device
> /sys/class/net/eth1/device
> /sys/class/input/input1/ts0/device
> /sys/class/input/input1/mouse0/device
> /sys/class/input/input1/event1/device
> /sys/class/input/input1/device
> /sys/class/input/input0/event0/device
> /sys/class/input/input0/device
> {pts/1}% uname -a
> Linux cooker 2.6.20-rc5-1avb #10 Sat Jan 13 14:05:34 MSK 2007 i686 Pentium
> III (Coppermine) GNU/Linux
Because I haven't finished converting all of the different usages of
struct class_device to struct device just yet. When that happens, those
links go away, as the /sys/class/foo_class/foo is a symlink itself into
the /sys/devices/ tree.
If you look in the -mm tree there is a patch for the network devices,
and I have patches in my tree (but not -mm) for pcmcia, usb_host,
usb_device, and input. These patches still need a bit of work before
sending them on to their relative maintainers for acceptance.
Hope this helps explain things,
greg k-h
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Re: No more "device" symlinks for classes
Pierre Ossman wrote:
> Hi guys,
>
> I just wanted to know the rationale behind
> 99ef3ef8d5f2f5b5312627127ad63df27c0d0d05 (no more "device" symlink in
> class devices). I thought that was a rather convenient way of finding
> which physical device the class device was coupled to.
>
Actually I wonder why those links still present even when I told system not
to create them?
{pts/1}% grep DEPRE /boot/config
# CONFIG_SYSFS_DEPRECATED is not set
# CONFIG_PM_SYSFS_DEPRECATED is not set
{pts/1}% find /sys/class -name device
/sys/class/pcmcia_socket/pcmcia_socket2/device
/sys/class/pcmcia_socket/pcmcia_socket1/device
/sys/class/pcmcia_socket/pcmcia_socket0/device
/sys/class/usb_device/usbdev1.1/device
/sys/class/usb_host/usb_host1/device
/sys/class/scsi_disk/0:0:0:0/device
/sys/class/scsi_device/1:0:0:0/device
/sys/class/scsi_device/0:0:0:0/device
/sys/class/scsi_host/host1/device
/sys/class/scsi_host/host0/device
/sys/class/net/eth0/device
/sys/class/net/eth1/device
/sys/class/input/input1/ts0/device
/sys/class/input/input1/mouse0/device
/sys/class/input/input1/event1/device
/sys/class/input/input1/device
/sys/class/input/input0/event0/device
/sys/class/input/input0/device
{pts/1}% uname -a
Linux cooker 2.6.20-rc5-1avb #10 Sat Jan 13 14:05:34 MSK 2007 i686 Pentium
III (Coppermine) GNU/Linux
-andrey
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Re: No more "device" symlinks for classes
On Sun, 2007-01-14 at 01:29 +0100, Pierre Ossman wrote: > Kay Sievers wrote: > > > > The plan is to have a single unified tree at /sys/devices, where all > > device-directories live below their parents, and /sys/class contains > > only symlinks pointing into this single tree, just like /sys/bus. > > > > People want to stack class-devices, but this leads to a /sys/devices > > tree and several small trees spread around in /sys/class. These trees > > need to be connected by "device"-links and the "class:"-links, which > > just doesn't make much sense if you can have one single tree with the > > same information. > > > > In the unified tree, the "device"-link will always just point to the > > parent device, that's why there is a config option to disable these > > links and test current software not to depend on it. > > > I'm not sure I completely follow. Should an application look at the > symlink (e.g. /sys/class/fooclass/foodev -> /sys/devices/...) and follow > that one level up? If so, then this sounds a bit complicated. Especially > from shell scripts. We would have one single tree at /sys/devices, and always flat classification without hierarchy at /sys/class and /sys/bus. If you enter the device-tree by starting at /sys/class, you get the full path to the device by reading the link, and get all the device's dependencies(parents) in the devpath of the device, I can't see any problem stripping the last element of a path with a shell script. It's all implemented in current udev and HAL for quite some time and it's pretty easy. Kay - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: No more "device" symlinks for classes
Kay Sievers wrote: > > The plan is to have a single unified tree at /sys/devices, where all > device-directories live below their parents, and /sys/class contains > only symlinks pointing into this single tree, just like /sys/bus. > > People want to stack class-devices, but this leads to a /sys/devices > tree and several small trees spread around in /sys/class. These trees > need to be connected by "device"-links and the "class:"-links, which > just doesn't make much sense if you can have one single tree with the > same information. > > In the unified tree, the "device"-link will always just point to the > parent device, that's why there is a config option to disable these > links and test current software not to depend on it. > > I'm not sure I completely follow. Should an application look at the symlink (e.g. /sys/class/fooclass/foodev -> /sys/devices/...) and follow that one level up? If so, then this sounds a bit complicated. Especially from shell scripts. Rgds -- -- Pierre Ossman Linux kernel, MMC maintainerhttp://www.kernel.org PulseAudio, core developer http://pulseaudio.org rdesktop, core developer http://www.rdesktop.org - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: No more "device" symlinks for classes
On Sun, 2007-01-14 at 00:51 +0100, Pierre Ossman wrote: > I just wanted to know the rationale behind > 99ef3ef8d5f2f5b5312627127ad63df27c0d0d05 (no more "device" symlink in > class devices). I thought that was a rather convenient way of finding > which physical device the class device was coupled to. The plan is to have a single unified tree at /sys/devices, where all device-directories live below their parents, and /sys/class contains only symlinks pointing into this single tree, just like /sys/bus. People want to stack class-devices, but this leads to a /sys/devices tree and several small trees spread around in /sys/class. These trees need to be connected by "device"-links and the "class:"-links, which just doesn't make much sense if you can have one single tree with the same information. In the unified tree, the "device"-link will always just point to the parent device, that's why there is a config option to disable these links and test current software not to depend on it. There was a long discussion on lkml about all that, maybe a year ago, while converting "input". Thanks, Kay - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
