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@xxxxxxxxx>
Cc: Carlos Corbacho <carlos@xxxxxxxxxxxxxxxxxxx>
Cc: Matthew Garrett <mjg@xxxxxxxxxx>
Cc: Dmitry Torokhov <dtor@xxxxxxx>
Cc: Corentin Chary <corentincj@xxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Aaron Lu <aaron.lu@xxxxxxxxx>
Cc: Thomas Renninger <trenn@xxxxxxx>
Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx>
---
drivers/acpi/video.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/acpi/video.h | 2 +
2 files changed, 56 insertions(+), 0 deletions(-)
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index c3932d0..f21104d 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -1861,6 +1861,60 @@ 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;
+
+ if (acpi_bus_get_device(handle, &acpi_dev))
+ return AE_OK;
+
+ if (!acpi_match_device_ids(acpi_dev, video_device_ids)) {
+ video = acpi_driver_data(acpi_dev);
+ 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);
+ }
+ return AE_OK;
+}
+
+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;
+ }
+ 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)
{
--
1.6.4.2
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