Improve battery hwmon searching for newer kernels

backend/Cargo.lock

@@ -1043,7 +1043,7 @@ dependencies = [
 
 [[package]]
 name = "powertools"
-version = "1.4.0-alpha2"
+version = "1.4.0-beta1"
 dependencies = [
  "async-trait",
  "libryzenadj",

backend/src/settings/steam_deck/battery.rs

@@ -284,12 +284,23 @@ impl Battery {
                 }
                 hwmon
             },
+            Err(e) => {
+                log::warn!("Failed to find SteamDeck battery hwmon {} in sysfs ({}), trying alternate name",
+                           super::util::JUPITER_HWMON_NAME, e);
+                match root.hwmon_by_name(super::util::STEAMDECK_HWMON_NAME) {
+                    Ok(hwmon) => {
+                        if !hwmon.capable(attributes(HWMON_NEEDS.into_iter().copied())) {
+                            log::warn!("Found incapable SteamDeck battery hwmon in sysfs (hwmon by name {} exists but missing attributes), persevering because ignorance is bliss", super::util::STEAMDECK_HWMON_NAME);
+                        }
+                        hwmon
+                    },
                     Err(e) => {
                         log::error!("Failed to find SteamDeck battery hwmon in sysfs ({}), using naive fallback", e);
                         root.hwmon_by_index(5)
                     }
             }
         }
+    }
 
     #[inline]
     fn charge_mode_to_str(mode: ChargeMode) -> String {
@@ -550,7 +561,23 @@ impl OnPowerEvent for Battery {
             PowerMode::BatteryCharge(_) => Ok(()),
         }
         .unwrap_or_else(|mut e| errors.append(&mut e));
+        let new_charge_control_attr = HwMonAttribute::custom("max_battery_charge_level");
+        let attr_exists = new_charge_control_attr.exists(&*self.sysfs_hwmon);
+        log::info!("Does battery limit attribute (max_battery_charge_level) exist? {}", attr_exists);
         for ev in &mut self.events {
+            if attr_exists {
+                if let EventTrigger::BatteryAbove(level) = ev.trigger {
+                    if let Some(ChargeMode::Idle) = ev.charge_mode {
+                        self.sysfs_hwmon.set(new_charge_control_attr, (level * 100.0).round() as u64)
+                            .unwrap_or_else(|e| errors.push(
+                                SettingError {
+                                    msg: format!("Failed to write to {:?}: {}", new_charge_control_attr, e),
+                                    setting: crate::settings::SettingVariant::Battery,
+                                }
+                            ));
+                    }
+                }
+            }
             ev.on_power_event(new_mode)
                 .unwrap_or_else(|mut e| errors.append(&mut e));
         }

backend/src/settings/steam_deck/util.rs

@@ -9,6 +9,7 @@ use std::fs::OpenOptions;
 use std::io::{Error, Read, Seek, SeekFrom, Write};
 
 pub const JUPITER_HWMON_NAME: &'static str = "jupiter";
+pub const STEAMDECK_HWMON_NAME: &'static str = "steamdeck_hwmon";
 pub const GPU_HWMON_NAME: &'static str = "amdgpu";
 
 #[inline]