From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> 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. [hdegoede@xxxxxxxxxx: Move the delayed_work struct into struct acpi_video_device instead of having it as a global] [hdegoede@xxxxxxxxxx: Keep brightness_switch_enabled as a boolean and always delay the keypress handling] Tested-by: Hans de Goede <hdegoede@xxxxxxxxxx> Tested-by: Bjørn Mork <bjorn@xxxxxxx> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> -- Changes in v2: -Keep brightness_switch_enabled as a boolean and always delay the handling --- drivers/acpi/video.c | 44 +++++++++++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 17 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 1a450c9..18c0e69 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -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]); } @@ -1252,6 +1254,8 @@ 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); @@ -1474,15 +1478,18 @@ 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; @@ -1504,8 +1511,6 @@ 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, @@ -1673,6 +1678,16 @@ 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; @@ -1690,28 +1705,23 @@ 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: -- 2.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
