On Thu, Nov 22, 2012 at 10:20 PM, Grant Likely <[email protected]> wrote: > On Thu, Nov 22, 2012 at 7:17 PM, Kay Sievers <[email protected]> wrote: >> On Wed, Nov 21, 2012 at 3:52 PM, Greg Kroah-Hartman >> <[email protected]> wrote:
>>> If the devices don't show up under platform/ where are they going to be >>> at now, virtual/ ? That doesn't sound like a good plan, they should be >>> somewhere "useful". >> >> Just a note to keep in mind: We usually need and want devices to have >> a bus or class. Devices without a "subsystem" are invisible to udev, >> and do not get proper coldplug support at bootup. > > Note: this patch is only about the "platform_bus" dummy device. It has > nothing to do with platform_bus_type. Ah, I see now. Why do you want to remove the "platform_bus" fake-parent, entirely? I understand and agree that drivers should not fiddle with that directly. But I don't see a real reason why it should not be private to the platform_bus_type. It's nothing really wrong with it, I guess. I have on x86: coretemp.0 -> ../../../devices/platform/coretemp.0 dock.0 -> ../../../devices/platform/dock.0 dock.1 -> ../../../devices/platform/dock.1 efifb.0 -> ../../../devices/platform/efifb.0 i8042 -> ../../../devices/platform/i8042 iTCO_wdt -> ../../../devices/pci0000:00/0000:00:1f.0/iTCO_wdt pcspkr -> ../../../devices/platform/pcspkr serial8250 -> ../../../devices/platform/serial8250 thinkpad_acpi -> ../../../devices/platform/thinkpad_acpi thinkpad_hwmon -> ../../../devices/platform/thinkpad_hwmon which look pretty reasonable in a "platform parent" instead of ending up in virtual/. We should probably remove the explicit assignment in the drivers like your patch does, unexport "platform_bus" from the core, so nobody can use it anymore in the future. The /sys/bus/platform/devices/ directory can then be created on-demand only, with the first registration of a device without a parent, we do that in other parts of the core already. Wouldn't that solve your problem and still do not touch any other stuff visible in /sys? Also, it seems there are devices without any subsystem in the list of things your patch touches? That is really not how things should work. All devices should have a bus or class, so userspace receives proper events, and can enumerate them. The /sys/devices/ hierarchy is not really meant to be used directly, it can for some devices even change at runtime. It's not considered a stable or reasonable predictable ABI, all lookups should start in the flat device symlink lists of the class/ and bus/, and not in the hierarchical tree in devices/. 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/
