[PATCH 3/3] PCI Hotplug: workaround for Thunderbolt on Intel DZ77RE-75K motherboard

["Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>]

From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>

BIOS on Intel DZ77RE-75K motherboard notifies OS about Thunderbolt
hotplug before devices behind Thunderbolt are ready to be enumerated.

Let's delay enumeration by 2 seconds.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 drivers/pci/hotplug/acpiphp_glue.c |   16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 1a2b3ca..165987a 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -49,6 +49,7 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 
 #include "../pci.h"
 #include "acpiphp.h"
@@ -1327,6 +1328,19 @@ out:
 static void handle_hotplug_event_bridge(acpi_handle handle, u32 type,
 					void *context)
 {
+	unsigned long delay = 0;
+	const char *board_name;
+
+	board_name = dmi_get_system_info(DMI_BOARD_NAME);
+	/*
+	 * BIOS on Intel DZ77RE-75K motherboard notifies OS about Thunderbolt
+	 * hotplug before devices behind Thunderbolt are ready to be
+	 * enumerated.
+	 * Let's delay enumeration by 2 seconds.
+	 */
+	if (board_name && !strcmp(board_name, "DZ77RE-75K"))
+		delay = 2 * HZ;
+
 	/*
 	 * Currently the code adds all hotplug events to the kacpid_wq
 	 * queue when it should add hotplug events to the kacpi_hotplug_wq.
@@ -1336,7 +1350,7 @@ static void handle_hotplug_event_bridge(acpi_handle handle, u32 type,
 	 * don't deadlock on hotplug actions.
 	 */
 	alloc_acpiphp_hp_work(handle, type, context,
-			      _handle_hotplug_event_bridge, 0);
+			      _handle_hotplug_event_bridge, delay);
 }
 
 static void _handle_hotplug_event_func(struct work_struct *work)
-- 
1.7.10.4