CLI args for bios. Cleanup and improve

- dbus method for 'supported modes'
- add dedicated gfx safety
- bring ctrl-gfx back in to main control for better integration
- safely upgrade config files

asus-nb-ctrl/src/ctrl_gfx/error.rs

@@ -0,0 +1,30 @@
+use std::error;
+use std::fmt;
+
+#[derive(Debug)]
+pub enum GfxError {
+    ParseVendor,
+    Path(String, std::io::Error),
+    Read(String, std::io::Error),
+    Write(String, std::io::Error),
+    Module(String, std::io::Error),
+    Bus(String, std::io::Error),
+    Command(String, std::io::Error),
+}
+
+impl fmt::Display for GfxError {
+    // This trait requires `fmt` with this exact signature.
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            GfxError::ParseVendor => write!(f, "Could not parse vendor name"),
+            GfxError::Path(path, error) => write!(f, "Path {}: {}", path, error),
+            GfxError::Read(path, error) => write!(f, "Read {}: {}", path, error),
+            GfxError::Write(path, error) => write!(f, "Write {}: {}", path, error),
+            GfxError::Module(func, error) => write!(f, "Module error: {}: {}", func, error),
+            GfxError::Bus(func, error) => write!(f, "Bus error: {}: {}", func, error),
+            GfxError::Command(func, error) => write!(f, "Command exec error: {}: {}", func, error),
+        }
+    }
+}
+
+impl error::Error for GfxError {}