kern/93738: ukbd_check_char returns FALSE with character buffered

[Norbert Koch]

>Number:         93738
>Category:       kern
>Synopsis:       ukbd_check_char returns FALSE with character buffered
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Feb 23 09:30:08 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Norbert Koch
>Release:        RELENG-4/RELENG-6
>Organization:
>Environment:
>Description:
When playing around with kbdmux I found scan codes coming from
my (secondary) usb keyboard mixed with those coming from
my primary keyboard.

An Example:
  1. Numpad-Enter on the usb keyboard
  2. ESC on the ps/2 keyboard
  3. Numpad-Enter on the usb keyboard

This results in the following sequence:
  E0 1C E0 01 81 9C E0 1C E0
  ++++++++ +++++ ++ ++++++++
  |        |     |  |
  |        |     |  2nd Numpad-Enter withount break code
  |        |     |
  |        |     break code for 1st Numpad-Enter
  |        |
  |        break/make for ESC
  |
  1st Numpad-Enter without break code

The problem is in ukbd_check_char() which is different
from ukbd_check() in not testing ks_buffered[0].

This leads to ukbd returning the missing break code with
the next key pressed on the usb keyboard.

This obviously results in a lot of trouble with kbdmux.
I managed to have the Xserver returning a permanent
state of ctrl key pressed.

>How-To-Repeat:
              
>Fix:
This patch is against current.


          --- ukbd.c.orig Thu Feb 23 09:48:44 2006
+++ ukbd.c      Thu Feb 23 09:55:00 2006
@@ -1143,6 +1143,10 @@
        if (!KBD_IS_ACTIVE(kbd))
                return FALSE;
        state = (ukbd_state_t *)kbd->kb_data;
+#ifdef UKBD_EMULATE_ATSCANCODE
+       if (state->ks_buffered_char[0])
+               return TRUE;
+#endif
        if (!(state->ks_flags & COMPOSE) && (state->ks_composed_char > 0))
                return TRUE;
        if (state->ks_inputs > 0)
    

>Release-Note:
>Audit-Trail:
>Unformatted: