chore(core): add missing parameter to set_brightness function

core/.changelog.d/4410.fixed

@@ -0,0 +1 @@
+Add optional value parameter in brightness setting flow.

core/embed/rust/src/ui/model_mercury/flow/set_brightness.rs

@@ -65,7 +65,16 @@ impl FlowController for SetBrightness {
 static BRIGHTNESS: AtomicU8 = AtomicU8::new(0);
 
 pub fn new_set_brightness(brightness: Option<u8>) -> Result<SwipeFlow, Error> {
-    let brightness = brightness.unwrap_or(theme::backlight::get_backlight_normal());
+    let brightness = brightness
+        .map(|value| {
+            // If brightness value is provided, set display brightness to that value
+            display::backlight(value as _);
+            BRIGHTNESS.store(value as u8, Ordering::Relaxed);
+            let _ = storage::set_brightness(BRIGHTNESS.load(Ordering::Relaxed));
+            value
+        })
+        .unwrap_or_else(|| theme::backlight::get_backlight_normal() as _);
+
     let content_slider = Frame::left_aligned(
         TR::brightness__title.into(),
         NumberInputSliderDialog::new(

core/src/apps/management/set_brightness.py

@@ -4,7 +4,7 @@ if TYPE_CHECKING:
     from trezor.messages import SetBrightness, Success
 
 
-async def set_brightness(_msg: SetBrightness) -> Success:
+async def set_brightness(msg: SetBrightness) -> Success:
     import storage.device as storage_device
     from trezor.messages import Success
     from trezor.ui.layouts import set_brightness
@@ -13,5 +13,5 @@ async def set_brightness(_msg: SetBrightness) -> Success:
     if not storage_device.is_initialized():
         raise NotInitialized("Device is not initialized")
 
-    await set_brightness()
+    await set_brightness(msg.value)
     return Success(message="Settings applied")

tests/device_tests/test_msg_applysettings.py

@@ -424,13 +424,32 @@ def test_label_too_long(client: Client):
 
 
 @pytest.mark.models(skip=["legacy", "safe3"])
+@pytest.mark.parametrize(
+    "value",
+    [
+        pytest.param(None, id="none_default"),
+        pytest.param(
+            -1,
+            marks=pytest.mark.xfail(),
+            id="negative_value",
+        ),
+        pytest.param(0, id="0_min_value"),
+        pytest.param(128, id="128"),
+        pytest.param(255, id="255_max_value"),
+        pytest.param(
+            256,
+            marks=pytest.mark.xfail(),
+            id="256_too_high",
+        ),
+    ],
+)
 @pytest.mark.setup_client(pin=None)
-def test_set_brightness(client: Client):
+def test_set_brightness(client: Client, value: int | None):
     with client:
         assert (
             device.set_brightness(
                 client,
-                None,
+                value,
             )
             == "Settings applied"
         )