From: Rafael J. Wysocki on
There is a problem with the ACPI video resume routine that it's
executed before the GPU that may be accessed by it. To fix this
issue, move the ACPI video resume to a power management notifier,
so that it's executed after resuming all devices, including the GPU.

Signed-off-by: Rafael J. Wysocki <rjw(a)sisk.pl>
---
drivers/acpi/video.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)

Index: linux-2.6/drivers/acpi/video.c
===================================================================
--- linux-2.6.orig/drivers/acpi/video.c
+++ linux-2.6/drivers/acpi/video.c
@@ -43,6 +43,7 @@
#include <linux/dmi.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
+#include <linux/suspend.h>

#define PREFIX "ACPI: "

@@ -88,7 +89,6 @@ module_param(allow_duplicates, bool, 064
static int register_count = 0;
static int acpi_video_bus_add(struct acpi_device *device);
static int acpi_video_bus_remove(struct acpi_device *device, int type);
-static int acpi_video_resume(struct acpi_device *device);
static void acpi_video_bus_notify(struct acpi_device *device, u32 event);

static const struct acpi_device_id video_device_ids[] = {
@@ -104,7 +104,6 @@ static struct acpi_driver acpi_video_bus
.ops = {
.add = acpi_video_bus_add,
.remove = acpi_video_bus_remove,
- .resume = acpi_video_resume,
.notify = acpi_video_bus_notify,
},
};
@@ -159,6 +158,7 @@ struct acpi_video_bus {
struct proc_dir_entry *dir;
struct input_dev *input;
char phys[32]; /* for input device */
+ struct notifier_block pm_nb;
};

struct acpi_video_device_flags {
@@ -2226,24 +2226,31 @@ static void acpi_video_device_notify(acp
return;
}

-static int instance;
-static int acpi_video_resume(struct acpi_device *device)
+static int acpi_video_resume(struct notifier_block *nb,
+ unsigned long val, void *ign)
{
struct acpi_video_bus *video;
struct acpi_video_device *video_device;
int i;

- if (!device || !acpi_driver_data(device))
- return -EINVAL;
+ switch (val) {
+ case PM_HIBERNATION_PREPARE:
+ case PM_SUSPEND_PREPARE:
+ case PM_RESTORE_PREPARE:
+ return NOTIFY_DONE;
+ }

- video = acpi_driver_data(device);
+ video = container_of(nb, struct acpi_video_bus, pm_nb);
+
+ dev_info(&video->device->dev, "Restoring backlight state\n");

for (i = 0; i < video->attached_count; i++) {
video_device = video->attached_array[i].bind_info;
if (video_device && video_device->backlight)
acpi_video_set_brightness(video_device->backlight);
}
- return AE_OK;
+
+ return NOTIFY_OK;
}

static acpi_status
@@ -2267,6 +2274,8 @@ acpi_video_bus_match(acpi_handle handle,
return AE_OK;
}

+static int instance;
+
static int acpi_video_bus_add(struct acpi_device *device)
{
struct acpi_video_bus *video;
@@ -2360,6 +2369,10 @@ static int acpi_video_bus_add(struct acp
video->flags.rom ? "yes" : "no",
video->flags.post ? "yes" : "no");

+ video->pm_nb.notifier_call = acpi_video_resume;
+ video->pm_nb.priority = 0;
+ register_pm_notifier(&video->pm_nb);
+
return 0;

err_free_input_dev:
@@ -2386,6 +2399,8 @@ static int acpi_video_bus_remove(struct

video = acpi_driver_data(device);

+ unregister_pm_notifier(&video->pm_nb);
+
acpi_video_bus_stop_devices(video);
acpi_video_bus_put_devices(video);
acpi_video_bus_remove_fs(device);
--
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