Add verbose error for LED node missing

asus-nb-ctrl/src/ctrl_leds.rs

@@ -152,7 +152,12 @@ impl crate::CtrlTask for CtrlKbdBacklight {
         let mut file = OpenOptions::new()
             .read(true)
             .open(&self.bright_node)
-            .map_err(|err| RogError::Path((&self.bright_node).into(), err))?;
+            .map_err(|err| {
+                match err.kind() {
+                    std::io::ErrorKind::NotFound => RogError::MissingLedBrightNode((&self.bright_node).into(), err),
+                    _ => RogError::Path((&self.bright_node).into(), err),
+                }
+            })?;
         let mut buf = [0u8; 1];
         file.read_exact(&mut buf)
             .map_err(|err| RogError::Read("buffer".into(), err))?;

asus-nb-ctrl/src/error.rs

@@ -1,7 +1,7 @@
-use std::fmt;
-use std::convert::From;
 use intel_pstate::PStateError;
 use rog_fan_curve::CurveError;
+use std::convert::From;
+use std::fmt;
 
 #[derive(Debug)]
 pub enum RogError {
@@ -19,6 +19,7 @@ pub enum RogError {
     FanCurve(CurveError),
     DoTask(String),
     MissingFunction(String),
+    MissingLedBrightNode(String, std::io::Error),
 }
 
 impl fmt::Display for RogError {
@@ -39,6 +40,7 @@ impl fmt::Display for RogError {
             RogError::FanCurve(err) => write!(f, "Custom fan-curve error: {}", err),
             RogError::DoTask(deets) => write!(f, "Task error: {}", deets),
             RogError::MissingFunction(deets) => write!(f, "Missing functionality: {}", deets),
+            RogError::MissingLedBrightNode(path, error) => write!(f, "Led node at {} is missing, please check you have the required patch or dkms module installed: {}", path, error),
         }
     }
 }
@@ -55,4 +57,4 @@ impl From<CurveError> for RogError {
     fn from(err: CurveError) -> Self {
         RogError::FanCurve(err)
     }
-}
+}