From: Hans de Goede <hdegoede@xxxxxxxxxx> [ Upstream commit 4f7f96453b462b3de0fa18d18fe983960bb5ee7f ] Some machines change the brightness themselves when a brightness hotkey gets pressed, despite us telling them not to. This causes the brightness to go two steps up / down when the hotkey is pressed. This is esp. a problem on older machines with only a few brightness levels. This commit adds a new hw_changes_brightness quirk which makes acpi_video_device_notify() only call backlight_force_update(..., BACKLIGHT_UPDATE_HOTKEY) and not do anything else, notifying userspace that the brightness was changed and leaving it at that fixing the dual step problem. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=204077 Reported-by: Kacper Piwiński <cosiekvfj@xxxxx> Tested-by: Kacper Piwiński <cosiekvfj@xxxxx> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/acpi/acpi_video.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index 9489ffc064117..4f325e47519f5 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -60,6 +60,12 @@ module_param(report_key_events, int, 0644); MODULE_PARM_DESC(report_key_events, "0: none, 1: output changes, 2: brightness changes, 3: all"); +static int hw_changes_brightness = -1; +module_param(hw_changes_brightness, int, 0644); +MODULE_PARM_DESC(hw_changes_brightness, + "Set this to 1 on buggy hw which changes the brightness itself when " + "a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness"); + /* * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be * assumed even if not actually set. @@ -405,6 +411,14 @@ static int video_set_report_key_events(const struct dmi_system_id *id) return 0; } +static int video_hw_changes_brightness( + const struct dmi_system_id *d) +{ + if (hw_changes_brightness == -1) + hw_changes_brightness = 1; + return 0; +} + static const struct dmi_system_id video_dmi_table[] = { /* * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121 @@ -529,6 +543,21 @@ static const struct dmi_system_id video_dmi_table[] = { DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"), }, }, + /* + * Some machines change the brightness themselves when a brightness + * hotkey gets pressed, despite us telling them not to. In this case + * acpi_video_device_notify() should only call backlight_force_update( + * BACKLIGHT_UPDATE_HOTKEY) and not do anything else. + */ + { + /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */ + .callback = video_hw_changes_brightness, + .ident = "Packard Bell EasyNote MZ35", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"), + DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"), + }, + }, {} }; @@ -1612,6 +1641,14 @@ static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data) bus = video_device->video; input = bus->input; + if (hw_changes_brightness > 0) { + if (video_device->backlight) + backlight_force_update(video_device->backlight, + BACKLIGHT_UPDATE_HOTKEY); + acpi_notifier_call_chain(device, event, 0); + return; + } + switch (event) { case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS: /* Cycle brightness */ brightness_switch_event(video_device, event); -- 2.20.1
