ACPI, x86: fix Dell M6600 ACPI reboot regression via DMI

commit 76eb9a30db4bc8fd172f9155247264b5f2686d7b upstream.

Dell Precision M6600 is known to require PCI reboot, so add it to
the reboot blacklist in pci_reboot_dmi_table[].

https://bugzilla.kernel.org/show_bug.cgi?id=42749

cc: x86@kernel.org
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index d840e69..3034ee5 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -471,6 +471,14 @@
 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 		},
 	},
+	{	/* Handle problems with rebooting on the Precision M6600. */
+		.callback = set_pci_reboot,
+		.ident = "Dell OptiPlex 990",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
+		},
+	},
 	{ }
 };