xxxx

Author: phip1611

uefi/src/proto/console/serial.rs

@@ -187,21 +187,41 @@ impl Serial {
     /// # Errors
     ///
     /// - [`Status::DEVICE_ERROR`]: serial device reported an error
-    pub fn read_exact(&mut self, buffer: &mut [u8]) -> Result<()> {
+    pub fn read_exact(&mut self, buffer: &mut [u8]) -> Result<(), usize /* read bytes */> {
+        let stall_duration = if self.io_mode().baud_rate == 0 {
+            Duration::from_millis(1) } else {
+            let ms = 1_000_000 / self.io_mode().baud_rate;
+            Duration::from_millis(ms)
+        };
+        // Endless loop protection.
+        let max_timeout_count = buffer.len() * 5;
+
+        let mut timeout_count = 0;
         let mut remaining_buffer = buffer;
+
+        let move_buffer_by_n = |n| {
+            remaining_buffer = &mut remaining_buffer[n..];
+        };
+
+
         // We retry on timeout and only return other errors
         while !remaining_buffer.is_empty() {
             match self.read(remaining_buffer) {
                 Ok(_) => {
                     break;
                 }
-                Err(err) if err.status() == Status::TIMEOUT => {
-                    let n = *err.data();
-                    remaining_buffer = &mut remaining_buffer[n..];
-                    boot::stall(Duration::from_millis(1));
+                Err(err) if err.status() == Status::TIMEOUT && timeout_count < max_timeout_count => {
+                    timeout_count += 1;
+                    move_buffer_by_n(*err.data() /* n */);
+                    boot::stall(stall_duration);
+                },
+                Err(err) if err.status() == Status::TIMEOUT && timeout_count >= max_timeout_count => {
+                    move_buffer_by_n(*err.data() /* n */);
+                    let n_total = buffer.len() - remaining_buffer.len();
+                    return Err(Error::new(Status::TIMEOUT, n_total));
                 }
                 err => {
-                    return Err(Error::from(err.status()));
+                    return err
                 }
             }
         }