Add a new compile option SC_HISTORY_SIZE to specify the history buffer

size in terms of lines (instead of bytes).  When changing video mode
in ioctl SW_XXX commands, syscons checks scp->history_size and
allocate a history buffer at least as large as the new screen size.
(This was unnecessary before, because HISTORY_SIZE was as large as 100
lines and this is bigger than the maximum screen size: 60 lines).
Similar adjustment is done in ioctl CONS_HISTORY command too.

PR: kern/4169
Reviewed by: sos

2 files changed, 19 insertions, 14 deletions

diff --git a/sys/isa/syscons.c b/sys/isa/syscons.c
index 1dc6542..25bf831 100644
--- a/sys/isa/syscons.c
+++ b/sys/isa/syscons.c
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *  $Id: syscons.c,v 1.229 1997/08/08 22:52:30 sos Exp $
+ *  $Id: syscons.c,v 1.230 1997/08/09 19:24:03 sos Exp $
  */
 
 #include "sc.h"
@@ -961,16 +961,11 @@ scioctl(dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
                 return EBUSY;
 	    if (scp->history != NULL)
 		free(scp->history, M_DEVBUF);
-	    scp->history_size = *(int*)data;
-	    if (scp->history_size < scp->ysize)
-		scp->history = NULL;
-	    else {
-		scp->history_size *= scp->xsize;
-		scp->history_head = scp->history_pos = scp->history =
-		    (u_short *)malloc(scp->history_size*sizeof(u_short),
-				      M_DEVBUF, M_WAITOK);
-		bzero(scp->history_head, scp->history_size*sizeof(u_short));
-	    }
+	    scp->history_size = max(scp->ysize, *(int *)data)*scp->xsize;
+	    scp->history_head = scp->history_pos = scp->history =
+		(u_short *)malloc(scp->history_size*sizeof(u_short),
+				  M_DEVBUF, M_WAITOK);
+	    bzero(scp->history_head, scp->history_size*sizeof(u_short));
 	    return 0;
 	}
 	else
@@ -1183,6 +1178,13 @@ scioctl(dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
 	free(cut_buffer, M_DEVBUF);
     	cut_buffer = (char *)malloc(scp->xsize*scp->ysize, M_DEVBUF, M_NOWAIT);
 	cut_buffer[0] = 0x00;
+	if (scp->history != NULL)
+	    free(scp->history, M_DEVBUF);
+	scp->history_size = max(HISTORY_SIZE, scp->xsize*scp->ysize);
+	scp->history_head = scp->history_pos = scp->history = (u_short *)
+	    malloc(scp->history_size*sizeof(u_short), M_DEVBUF, M_NOWAIT);
+	if (scp->history != NULL)
+	    bzero(scp->history, scp->history_size*sizeof(u_short));
 	if (scp == cur_console)
 	    set_mode(scp);
 	scp->status &= ~UNKNOWN_MODE;
@@ -2812,7 +2814,7 @@ init_scp(scr_stat *scp)
     scp->proc = NULL;
     scp->smode.mode = VT_AUTO;
     scp->history_head = scp->history_pos = scp->history = NULL;
-    scp->history_size = HISTORY_SIZE;
+    scp->history_size = max(HISTORY_SIZE, scp->xsize*scp->ysize);
 }
 
 static u_char
diff --git a/sys/isa/syscons.h b/sys/isa/syscons.h
index 38c5ae4..578a71e 100644
--- a/sys/isa/syscons.h
+++ b/sys/isa/syscons.h
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *	$Id: syscons.h,v 1.31 1997/07/15 14:43:27 yokota Exp $
+ *	$Id: syscons.h,v 1.32 1997/08/25 23:21:55 bde Exp $
  */
 
 #ifndef _I386_ISA_SYSCONS_H_
@@ -101,7 +101,10 @@
 #define FONT_8		2
 #define FONT_14		4
 #define FONT_16		8
-#define HISTORY_SIZE	(COL * ROW * 4)
+#if !defined(SC_HISTORY_SIZE)
+#define SC_HISTORY_SIZE	(ROW * 4)
+#endif /* SC_HISTORY_SIZE */
+#define HISTORY_SIZE	(COL * (SC_HISTORY_SIZE))
 
 /* defines related to hardware addresses */
 #define	MONO_BASE	0x3B4			/* crt controller base mono */