Implement a simple hook (or hack?) to allow graphics device console

drivers to protect DDB from being invoked while the console is in
process-controlled (i.e., graphics) mode.

Implement the logic to use this hook from within pcvt.  (I'm sure
Søren will do the syscons part RSN).

I've still got one occasion where the system stalled, but my attempts
to trigger the situation artificially resulted int the expected
behaviour.  It's hard to track bugs without the console and DDB
available. :-/

1 files changed, 33 insertions, 1 deletions

diff --git a/sys/i386/isa/pcvt/pcvt_ext.c b/sys/i386/isa/pcvt/pcvt_ext.c
index 32a89a0..7088caf 100644
--- a/sys/i386/isa/pcvt/pcvt_ext.c
+++ b/sys/i386/isa/pcvt/pcvt_ext.c
@@ -2427,8 +2427,19 @@ vgapage(int new_screen)
 				psignal(vsp->proc, vsp->smode.acqsig);
 		}
 		else
+		{	
 			/* we are committed */
 			vt_switch_pending = 0;
+#if PCVT_FREEBSD > 206
+			/*
+			 * XXX: If pcvt is acting as the systems console,
+			 * avoid panics going to the debugger while we are in
+			 * process mode.
+			 */
+			if(pcvt_is_console)
+				cons_unavail = 0;
+#endif
+		}
 	}
 	return 0;
 }
@@ -2498,6 +2509,15 @@ usl_vt_ioctl(Dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
 		vsp->proc = p;
 		vsp->pid = p->p_pid;
 
+#if PCVT_FREEBSD > 206
+		/*
+		 * XXX: If pcvt is acting as the systems console,
+		 * avoid panics going to the debugger while we are in
+		 * process mode.
+		 */
+		if(pcvt_is_console)
+			cons_unavail = (newmode.mode == VT_PROCESS);
+#endif
 		splx(opri);
 		return 0;
 
@@ -2564,9 +2584,16 @@ usl_vt_ioctl(Dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
 							vsp->smode.acqsig);
 				}
 				else
+				{
 					/* we are committed */
 					vt_switch_pending = 0;
-				return 0;
+#if PCVT_FREEBSD > 206
+					/* XXX */
+					if(pcvt_is_console)
+						cons_unavail = 0;
+#endif
+					return 0;
+				}
 			}
 			break;
 			
@@ -2575,6 +2602,11 @@ usl_vt_ioctl(Dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
 			if(vsp->vt_status & VT_WAIT_ACK) {
 				vt_switch_pending = 0;
 				vsp->vt_status &= ~VT_WAIT_ACK;
+#if PCVT_FREEBSD > 206
+				/* XXX */
+				if(pcvt_is_console)
+					cons_unavail = 1;
+#endif
 				return 0;
 			}
 			break;