[PATCH 1/2 v2] acpi: video: add function to support unregister backlight interface

[PATCH 1/2 v2] acpi: video: add function to support unregister backlight interface

[Lee, Chun-Yi]

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: 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: Rafael J. Wysocki <rjw@sisk.pl>
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 |   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

[PATCH 2/2 v2] acer-wmi: add Acer Aspire 5750G to video vendor list but keep acpi video driver

[Lee, Chun-Yi]

After Andrzej's testing, we found the acpi backlight methods broken on Acer
Aspire 5750G but the i915 backlight control works when we set to vendor mode.
And, we still want to keep the acpi/video driver for transfer acpi event to key
event but not unregister whole acpi/video driver.

This patch introduced a new capability flag is ACER_CAP_KEEP_VIDEO_KEY, it
indicates the machine works fine with acpi/video driver for key event but want
to unregister the backlight interface of acpi/video.

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

v2: changed the information statement of keeping acpi video driver.

Tested-by: Andrzej Krentosz <endrjux@gmail.com>
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: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Thomas Renninger <trenn@suse.de>
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
---
 drivers/platform/x86/acer-wmi.c |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index c9076bd..a81c9ed 100644
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -207,6 +207,7 @@ struct hotkey_function_type_aa {
 #define ACER_CAP_BRIGHTNESS		(1<<3)
 #define ACER_CAP_THREEG			(1<<4)
 #define ACER_CAP_ACCEL			(1<<5)
+#define ACER_CAP_KEEP_VIDEO_KEY		(1<<6)
 #define ACER_CAP_ANY			(0xFFFFFFFF)
 
 /*
@@ -539,6 +540,15 @@ static int video_set_backlight_video_vendor(const struct dmi_system_id *d)
 	return 0;
 }
 
+static int video_set_backlight_video_vendor_keep_acpi_video(
+		const struct dmi_system_id *d)
+{
+	video_set_backlight_video_vendor(d);
+	interface->capability |= ACER_CAP_KEEP_VIDEO_KEY;
+	pr_info("Keeping acpi video driver active to emit backlight brightness change key events\n");
+	return 0;
+}
+
 static const struct dmi_system_id video_vendor_dmi_table[] = {
 	{
 		.callback = video_set_backlight_video_vendor,
@@ -572,6 +582,14 @@ static const struct dmi_system_id video_vendor_dmi_table[] = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5750"),
 		},
 	},
+	{
+		.callback = video_set_backlight_video_vendor_keep_acpi_video,
+		.ident = "Acer Aspire 5750G",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5750G"),
+		},
+	},
 	{}
 };
 
@@ -2228,6 +2246,8 @@ static int __init acer_wmi_init(void)
 	if (acpi_video_backlight_support()) {
 		interface->capability &= ~ACER_CAP_BRIGHTNESS;
 		pr_info("Brightness must be controlled by acpi video driver\n");
+	} else if (interface->capability & ACER_CAP_KEEP_VIDEO_KEY) {
+		acpi_video_backlight_unregister();
 	} else {
 		pr_info("Disabling ACPI video driver\n");
 		acpi_video_unregister();
-- 
1.6.4.2