* Add has_debugger_command() so whether or not a debugger command is available

can be checked.
* Make the usb_keyboard module check the presence of the needed debugger
  commands to avoid the error messages in case of them being unavailable.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29472 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/debug.h

@@ -142,6 +142,7 @@ extern status_t	add_debugger_command_etc(const char* name,
 extern status_t	add_debugger_command_alias(const char* newName,
 					const char* oldName, const char* description);
 extern bool		print_debugger_command_usage(const char* command);
+extern bool		has_debugger_command(const char* command);
 
 extern const char *debug_demangle_symbol(const char* symbol, char* buffer,
 					size_t bufferSize, bool* _isObjectMethod);

src/add-ons/kernel/debugger/usb_keyboard/usb_keyboard.cpp

@@ -150,6 +150,12 @@ static size_t sKeyTableSize = sizeof(sKeyTable) / sizeof(sKeyTable[0]);
 static void
 enter_debugger(void)
 {
+	if (!has_debugger_command("get_usb_keyboard_config")
+		|| !has_debugger_command("get_usb_pipe_for_id")
+		|| (!has_debugger_command("uhci_process_transfer")
+			&& !has_debugger_command("ohci_process_transfer")))
+		return;
+
 	evaluate_debug_command("get_usb_keyboard_config");
 	sUSBTransferLength = get_debug_variable("_usbReportSize", 0);
 	if (sUSBTransferLength == 0 || sUSBTransferLength > sizeof(sUSBTransferData))

src/system/kernel/debug/debug_commands.cpp

@@ -496,6 +496,14 @@ print_debugger_command_usage(const char* commandName)
 }
 
 
+bool
+has_debugger_command(const char* commandName)
+{
+	bool ambiguous;
+	return find_debugger_command(commandName, false, ambiguous) != NULL;
+}
+
+
 //	#pragma mark - public API
 
 int