* Added arch_debug_blue_screen_try_getchar() and arch_debug_serial_try_getchar()

which don't wait for a character, but return -1 when no character is
  available ATM. Implemented correctly for x86 only.
* Changed the semantics of the debugger_module_info::debugger_getchar() hook.
  It is supposed to return immediately now.
* Adjusted usb_keyboard accordingly. Hacked UHCI's debug_process_transfer() to
  achieve that. It does now start, check, or cancel a transfer. Split
  UHCI::ProcessDebugTransfer() into StartDebugTransfer(), and
  CheckDebugTransfer() accordingly, and also added a CancelDebugTransfer().
  The latter seems to have issues. Michael, please have a look. I have no clue
  what I'm doing. :-)
* Adjusted kgetc() to poll all possible inputs using the new
  functions/semantics. This allows to use any input (USB, PS/2, serial) in KDL.
* Removed the no longer needed "serial_input" command.
* read_line(): Also support 0x7f as backspace code. That's what xterm sends.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42126 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/arch/debug_console.h

@@ -1,4 +1,4 @@
-/* 
+/*
  * Copyright 2002-2006, Axel Dörfler, [email protected]
  * Distributed under the terms of the MIT License.
  *
@@ -18,7 +18,9 @@ struct kernel_args;
 extern "C" {
 #endif
 
+int arch_debug_blue_screen_try_getchar(void);
 char arch_debug_blue_screen_getchar(void);
+int arch_debug_serial_try_getchar(void);
 char arch_debug_serial_getchar(void);
 void arch_debug_serial_putchar(char c);
 void arch_debug_serial_puts(const char *s);