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ACPI / video: Fix backlight taking 2 steps on a brightness up/down keypress 

In various scenarious userspace will respond to brightness up/down keypresses
by increasing/decreasing the backlight brightness itself. If the kernel then
also changes the brightness this results in the brightness having changed 2
steps for a single keypress which is undesirable. See e.g. :

https://bugs.launchpad.net/gnome-settings-daemon/+bug/527157
http://askubuntu.com/questions/173921/why-does-my-thinkpad-brightness-control-skip-steps

This commit delays responding to brightness up/down keypresses by 100 ms and
if userspace in that time responds by changing the backlight itself, cancels
the kernels own handling of these keypresses, fixing the 2 steps issue.

Link: http://marc.info/?l=linux-kernel&m=140535721100839&w=2
[hdegoede@redhat.com: Move the delayed_work struct into struct
 acpi_video_device instead of having it as a global]
[hdegoede@redhat.com: Keep brightness_switch_enabled as a boolean and always
 delay the keypress handling]
Tested-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Linus Torvalds 2014-07-18 14:32:51 +02:00 committed by Rafael J. Wysocki
parent 9a3c4145af
commit 8ab58e8e7e
1 changed files with 27 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
drivers/acpi/video.c
View File

@ -204,6 +204,8 @@ struct acpi_video_device {
struct acpi_video_device_flags flags;
struct acpi_video_device_cap cap;
struct list_head entry;
struct delayed_work switch_brightness_work;
int switch_brightness_event;
struct acpi_video_bus *video;
struct acpi_device *dev;
struct acpi_video_device_brightness *brightness;
@ -230,8 +232,7 @@ static int acpi_video_device_lcd_get_level_current(
unsigned long long *level, bool raw);
static int acpi_video_get_next_level(struct acpi_video_device *device,
u32 level_current, u32 event);
static int acpi_video_switch_brightness(struct acpi_video_device *device,
int event);
static void acpi_video_switch_brightness(struct work_struct *work);
static bool acpi_video_use_native_backlight(void)
{
@ -275,6 +276,7 @@ static int acpi_video_set_brightness(struct backlight_device *bd)
int request_level = bd->props.brightness + 2;
struct acpi_video_device *vd = bl_get_data(bd);
cancel_delayed_work(&vd->switch_brightness_work);
return acpi_video_device_lcd_set_level(vd,
vd->brightness->levels[request_level]);
}
@ -1188,6 +1190,8 @@ acpi_video_bus_get_one_device(struct acpi_device *device,
data->device_id = device_id;
data->video = video;
data->dev = device;
INIT_DELAYED_WORK(&data->switch_brightness_work,
acpi_video_switch_brightness);
attribute = acpi_video_get_device_attr(video, device_id);
@ -1410,15 +1414,18 @@ acpi_video_get_next_level(struct acpi_video_device *device,
}
}
static int
acpi_video_switch_brightness(struct acpi_video_device *device, int event)
static void
acpi_video_switch_brightness(struct work_struct *work)
{
struct acpi_video_device *device = container_of(to_delayed_work(work),
struct acpi_video_device, switch_brightness_work);
unsigned long long level_current, level_next;
int event = device->switch_brightness_event;
int result = -EINVAL;
/* no warning message if acpi_backlight=vendor or a quirk is used */
if (!acpi_video_verify_backlight_support())
return 0;
return;
if (!device->brightness)
goto out;
@ -1440,8 +1447,6 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event)
out:
if (result)
printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
return result;
}
int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
@ -1609,6 +1614,16 @@ static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
return;
}
static void brightness_switch_event(struct acpi_video_device *video_device,
u32 event)
{
if (!brightness_switch_enabled)
return;
video_device->switch_brightness_event = event;
schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
}
static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
{
struct acpi_video_device *video_device = data;
@ -1626,28 +1641,23 @@ static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
switch (event) {
case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS: /* Cycle brightness */
if (brightness_switch_enabled)
acpi_video_switch_brightness(video_device, event);
brightness_switch_event(video_device, event);
keycode = KEY_BRIGHTNESS_CYCLE;
break;
case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS: /* Increase brightness */
if (brightness_switch_enabled)
acpi_video_switch_brightness(video_device, event);
brightness_switch_event(video_device, event);
keycode = KEY_BRIGHTNESSUP;
break;
case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS: /* Decrease brightness */
if (brightness_switch_enabled)
acpi_video_switch_brightness(video_device, event);
brightness_switch_event(video_device, event);
keycode = KEY_BRIGHTNESSDOWN;
break;
case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
if (brightness_switch_enabled)
acpi_video_switch_brightness(video_device, event);
brightness_switch_event(video_device, event);
keycode = KEY_BRIGHTNESS_ZERO;
break;
case ACPI_VIDEO_NOTIFY_DISPLAY_OFF: /* display device off */
if (brightness_switch_enabled)
acpi_video_switch_brightness(video_device, event);
brightness_switch_event(video_device, event);
keycode = KEY_DISPLAY_OFF;
break;
default: