pciehp: fast unplug for virtual machinespcie-hotplug

The PCIe specification asks the OS to wait five seconds after the
attention button has been pressed before actually un-plugging the
device.  This gives the operator the chance to cancel the operation
by pressing the attention button again within those five seconds.

For physical hardware this makes sense.  Picking the wrong button
by accident can easily happen and it can be corrected that way.

For virtual hardware the benefits are questionable.  Typically
users find the five second delay annoying.

This patch adds the fast_virtual_unplug module parameter to the
pciehp driver.  When enabled (which is the default) the linux
kernel will simply skip the delay for virtual pcie ports, which
reduces the total time for the unplug operation from 6-7 seconds
to 1-2 seconds.

Virtual pcie ports are identified by PCI ID.  For now the qemu
pcie root ports are detected, other hardware can be added easily.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

0 files changed, 0 insertions, 0 deletions