tree 486e63a80e0f11d93f9f8ee3a5780b5030154cd0
parent 7e27d6e778cd87b6f2415515d7127eba53fe5d02
author Rafael J. Wysocki <rjw@sisk.pl> 1276873462 +0200
committer Jesse Barnes <jbarnes@virtuousgeek.org> 1276878997 -0700

PCI/PM: Do not use native PCIe PME by default

Commit c7f486567c1d0acd2e4166c47069835b9f75e77b
(PCI PM: PCIe PME root port service driver) causes the native PCIe
PME signaling to be used by default, if the BIOS allows the kernel to
control the standard configuration registers of PCIe root ports.
However, the native PCIe PME is coupled to the native PCIe hotplug
and calling pcie_pme_acpi_setup() makes some BIOSes expect that
the native PCIe hotplug will be used as well.  That, in turn, causes
problems to appear on systems where the PCIe hotplug driver is not
loaded.  The usual symptom, as reported by Jaroslav Kameník and
others, is that the ACPI GPE associated with PCIe hotplug keeps
firing continuously causing kacpid to take substantial percentage
of CPU time.

To work around this issue, change the default so that the native
PCIe PME signaling is only used if directly requested with the help
of the pcie_pme= command line switch.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=15924 , which is
a listed regression from 2.6.33.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Jaroslav Kameník <jaroslav@kamenik.cz>
Tested-by: Antoni Grzymala <antekgrzymala@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>