Disable debug mode and add comment for Issue esa-tu-darmstadt#296

Also leave some instructions on how to enable it again.

Debug mode is currently the same as unsafe mode due to libtapasco
not handling this case of access mode.
Additionally, the DMA Buffers, Interrupts, etc. are also allocated in
Monitor Mode which leads to the problem that you have to start your
other runtime twice. For this case I've added a comment in the help
section of `tapasco-debug`.

runtime/examples/Rust/tapasco-debug/src/app.rs

@@ -65,7 +65,7 @@ impl<'a> App<'a> {
         // Get Tapasco Loadable Linux Kernel Module
         let tlkm = TLKM::new().context(TLKMInit {})?;
         // Allocate the device with the given ID
-        let mut tlkm_device = tlkm
+        let tlkm_device = tlkm
             .device_alloc(device_id, &HashMap::new())
             .context(TLKMInit {})?;
 
@@ -77,13 +77,14 @@ impl<'a> App<'a> {
                 // no special access is necessary. This is a no-op.
                 "Monitor"
             }
-            AccessMode::Debug {} => {
-                // Change device access to exclusive to be able to acquire PEs
-                tlkm_device
-                    .change_access(tapasco::tlkm::tlkm_access::TlkmAccessExclusive)
-                    .context(DeviceInit {})?;
-                "Debug"
-            }
+            // TODO: 3. When Issue #296 is fixed, enable debug mode here again, too.
+            //AccessMode::Debug {} => {
+            //    // Change device access to exclusive to be able to acquire PEs
+            //    tlkm_device
+            //        .change_access(tapasco::tlkm::tlkm_access::TlkmAccessExclusive)
+            //        .context(DeviceInit {})?;
+            //    "Debug"
+            //}
             AccessMode::Unsafe {} => {
                 // Change device access to exclusive to be able to acquire PEs
                 warn!("Running in Unsafe Mode");
@@ -277,7 +278,9 @@ impl<'a> App<'a> {
         if self.tabs.index == 0 {
             match self.access_mode {
                 AccessMode::Monitor {} => {}
-                AccessMode::Debug {} | AccessMode::Unsafe {} => {
+                // TODO: 4. Replace the second next line with the next line:
+                // AccessMode::Debug {} | AccessMode::Unsafe {} => {
+                AccessMode::Unsafe {} => {
                     match self.input_mode {
                         InputMode::Normal => {
                             match self.focus {

runtime/examples/Rust/tapasco-debug/src/main.rs

@@ -25,8 +25,11 @@ type Result<T, E = Error> = std::result::Result<T, E>;
 
 use structopt::StructOpt;
 
+// TODO: 1. When issue #296 is fixed, remove the paragraph about the `EMFILE` error.
 /// The interactive `TaPaSCo` Debugger can be used to retrieve information about the loaded
 /// bitstream, monitor other `TaPaSCo` runtimes and write values to the registers of your PEs
+///
+/// Currently due to a `libtapasco` bug where DMA Buffers, Interrupts, etc. are allocated even in monitor mode, you will have to start your other runtime twice, where the first time the `EMFILE` error is to be expected.
 #[derive(StructOpt, Debug)]
 #[structopt(rename_all = "kebab-case")]
 struct Opt {
@@ -43,8 +46,9 @@ struct Opt {
 pub enum Command {
     /// Enter Monitor Mode where values cannot be modified, e.g. to monitor another runtime
     Monitor {},
-    /// Enter Debug Mode where values can only be modified interactively in this debugger
-    Debug {},
+    // TODO: 2. When issue #296 is fixed, enable debug mode again.
+    // /// Enter Debug Mode where values can only be modified interactively in this debugger
+    // Debug {},
     /// Enter Unsafe Mode where values can be modified by this debugger and another runtime
     Unsafe {},
 }