On Mon, Mar 12, 2012 at 8:10 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > On Sat, Mar 10, 2012 at 12:00 AM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: >> it supports both pci root bus and pci bus under pci bridge. >> >> -v2: Change to three returns way in dev_bus_remove_store. >> >> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> >> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxx> >> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> >> Cc: linux-doc@xxxxxxxxxxxxxxx >> --- >> Documentation/ABI/testing/sysfs-bus-pci | 8 ++++++++ >> drivers/pci/pci-sysfs.c | 30 ++++++++++++++++++++++++++++++ >> 2 files changed, 38 insertions(+), 0 deletions(-) >> >> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci >> index 95f0f37..22392de 100644 >> --- a/Documentation/ABI/testing/sysfs-bus-pci >> +++ b/Documentation/ABI/testing/sysfs-bus-pci >> @@ -92,6 +92,14 @@ Description: >> hot-remove the PCI device and any of its children. >> Depends on CONFIG_HOTPLUG. >> >> +What: /sys/bus/pci/devices/.../pci_bus/.../remove >> +Date: March 2012 >> +Contact: Linux PCI developers <linux-pci@xxxxxxxxxxxxxxx> >> +Description: >> + Writing a non-zero value to this attribute will >> + hot-remove the PCI bus and any of its children. >> + Depends on CONFIG_HOTPLUG. > > I don't think this interface makes sense. This stops every device on > the bus, removes the bus, unregisters the host bridge device if we're > removing a root bus. it is some kind of handy. otherwise if there is several devices on the bus, will need to remove the devices one by one. > > I think we should just have a "remove *bridge*" interface. It makes > no sense to me to remove a bus but leave the bridge, and it makes the > code quite complicated. I want to remove all devices under the bridge and then rescan the bridge. then if the bridge get removed. then we have to rescan bridge's parent bus. > > The point of hotplug is to add and remove devices. We'll get > interrupts saying "please remove this device" or "please rescan the > bus behind this bridge because something might have changed." > > If we're removing a host bridge, the platform, e.g., ACPI, will tell > us about the bridge that is going away. The notification is attached > to the *bridge*, not the bus it leads to. > > The expected mechanism on x86 is an SCI from the platform, but if we > need a sysfs way to start host bridge removal, I think it should be > something like this: > > echo 1 > /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/remove for that, let just use echo "\_SB.PCI0 3" > /proc/acpi/sci/notify Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
