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Subject[PATCH 1/3] acpi: video: add function to support unregister backlight interface
Date
From: "Lee, Chun-Yi" <joeyli.kernel@gmail.com>

There have some situation we unregister whole acpi/video driver by downstream
driver just want to remove backlight control interface of acpi/video. It caues
we lost other functions of acpi/video, e.g. transfer acpi event to input event.

So, this patch add a new function, find_video_unregister_backlight, it provide
the interface let downstream driver can tell acpi/video to unregister backlight
interface of all acpi video devices. Then we can keep functions of acpi/video
but only remove backlight support.

Reference: bko#35622
https://bugzilla.kernel.org/show_bug.cgi?id=35622

v2: Also unregister cooling devices.

Tested-by: Andrzej Krentosz <endrjux@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Corentin Chary <corentincj@iksaif.net>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Thomas Renninger <trenn@suse.de>
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
drivers/acpi/video.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++----
include/acpi/video.h | 2 ++
2 files changed, 89 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 5b32e15..da08ff7 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -43,6 +43,7 @@
#include <acpi/acpi_drivers.h>
#include <linux/suspend.h>
#include <acpi/video.h>
+#include <linux/mutex.h>

#define PREFIX "ACPI: "

@@ -86,6 +87,9 @@ module_param(allow_duplicates, bool, 0644);
static bool use_bios_initial_backlight = 1;
module_param(use_bios_initial_backlight, bool, 0644);

+static bool backlight_disable;
+module_param(backlight_disable, bool, 0644);
+
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);
@@ -214,6 +218,8 @@ static const char device_decode[][30] = {
"UNKNOWN",
};

+static DEFINE_MUTEX(backlight_mutex);
+
static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
static void acpi_video_device_rebind(struct acpi_video_bus *video);
static void acpi_video_device_bind(struct acpi_video_bus *video,
@@ -882,7 +888,7 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
device->cap._DDC = 1;
}

- if (acpi_video_backlight_support()) {
+ if (acpi_video_backlight_support() || backlight_disable) {
struct backlight_properties props;
struct pci_dev *pdev;
acpi_handle acpi_parent;
@@ -1083,15 +1089,22 @@ acpi_video_bus_get_one_device(struct acpi_device *device,
struct acpi_video_device *data;
struct acpi_video_device_attrib* attribute;

+ mutex_lock(&backlight_mutex);
+
status =
acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
/* Some device omits _ADR, we skip them instead of fail */
- if (ACPI_FAILURE(status))
- return 0;
+ if (ACPI_FAILURE(status)) {
+ status = 0;
+ goto out;
+ }

data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
- if (!data)
- return -ENOMEM;
+ if (!data) {
+ status = -ENOMEM;
+ goto out;
+ }
+

strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
@@ -1156,6 +1169,8 @@ acpi_video_bus_get_one_device(struct acpi_device *device,
list_add_tail(&data->entry, &video->video_device_list);
mutex_unlock(&video->device_list_lock);

+out:
+ mutex_unlock(&backlight_mutex);
return status;
}

@@ -1336,7 +1351,7 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event)
int result = -EINVAL;

/* no warning message if acpi_backlight=vendor is used */
- if (!acpi_video_backlight_support())
+ if (!acpi_video_backlight_support() || backlight_disable)
return 0;

if (!device->brightness)
@@ -1869,6 +1884,72 @@ static int __init intel_opregion_present(void)
return opregion;
}

+static acpi_status
+find_video_unregister_backlight(acpi_handle handle, u32 lvl, void *context,
+ void **rv)
+{
+ struct acpi_device *acpi_dev;
+ struct acpi_video_bus *video;
+ struct acpi_video_device *dev, *next;
+ acpi_status status = AE_OK;
+
+ mutex_lock(&backlight_mutex);
+
+ if (acpi_bus_get_device(handle, &acpi_dev))
+ goto out;
+
+ if (!acpi_match_device_ids(acpi_dev, video_device_ids)) {
+ video = acpi_driver_data(acpi_dev);
+
+ if (!video)
+ goto out;
+
+ acpi_video_bus_stop_devices(video);
+ mutex_lock(&video->device_list_lock);
+ list_for_each_entry_safe(dev, next, &video->video_device_list,
+ entry) {
+ if (dev->backlight) {
+ backlight_device_unregister(dev->backlight);
+ dev->backlight = NULL;
+ kfree(dev->brightness->levels);
+ kfree(dev->brightness);
+ }
+ if (dev->cooling_dev) {
+ sysfs_remove_link(&dev->dev->dev.kobj,
+ "thermal_cooling");
+ sysfs_remove_link(&dev->cooling_dev->device.kobj,
+ "device");
+ thermal_cooling_device_unregister(dev->cooling_dev);
+ dev->cooling_dev = NULL;
+ }
+ }
+ mutex_unlock(&video->device_list_lock);
+ acpi_video_bus_start_devices(video);
+ }
+out:
+ mutex_unlock(&backlight_mutex);
+ return status;
+}
+
+void acpi_video_backlight_unregister(void)
+{
+ if (!register_count) {
+ /*
+ * If the acpi video bus is already unloaded, don't
+ * unregister backlight of devices and return directly.
+ */
+ return;
+ }
+
+ backlight_disable = 1;
+
+ acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+ ACPI_UINT32_MAX, find_video_unregister_backlight,
+ NULL, NULL, NULL);
+ return;
+}
+EXPORT_SYMBOL(acpi_video_backlight_unregister);
+
int acpi_video_register(void)
{
int result = 0;
diff --git a/include/acpi/video.h b/include/acpi/video.h
index 61109f2..1e810a1 100644
--- a/include/acpi/video.h
+++ b/include/acpi/video.h
@@ -19,11 +19,13 @@ struct acpi_device;
#if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE)
extern int acpi_video_register(void);
extern void acpi_video_unregister(void);
+extern void acpi_video_backlight_unregister(void);
extern int acpi_video_get_edid(struct acpi_device *device, int type,
int device_id, void **edid);
#else
static inline int acpi_video_register(void) { return 0; }
static inline void acpi_video_unregister(void) { return; }
+static inline void acpi_video_backlight_unregister(void) { return; }
static inline int acpi_video_get_edid(struct acpi_device *device, int type,
int device_id, void **edid)
{
--
1.8.2.1


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