Comment 11 for bug 1257338

The above patch queued for 3.13 in for-linus branch from Bjorn Helgaas
https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/commit/?h=for-linus&id=4fc9bbf98fd66f879e628d8537ba7c240be2b58e

@Tarpoon: is not upstream yet, but you can git cherry-pick, or manual apply, etc.

[quote]
PCI: Disable Bus Master only on kexec reboot
Add a flag to tell the PCI subsystem that kernel is shutting down in
preparation to kexec a kernel. Add code in PCI subsystem to use this flag
to clear Bus Master bit on PCI devices only in case of kexec reboot.

This fixes a power-off problem on Acer Aspire V5-573G and likely other
machines and avoids any other issues caused by clearing Bus Master bit on
PCI devices in normal shutdown path. The problem was introduced by
b566a22c2332 ("PCI: disable Bus Master on PCI device shutdown").

This patch is based on discussion at
http://marc.info/?l=linux-pci&m=138425645204355&w=2

Link: https://bugzilla.kernel.org/show_bug.cgi?id=63861
Reported-by: Chang Liu <email address hidden>
Signed-off-by: Khalid Aziz <email address hidden>
Signed-off-by: Bjorn Helgaas <email address hidden>
Acked-by: Konstantin Khlebnikov <email address hidden>
Cc: <email address hidden> # v3.5+
[/quote]