Screen saver related fixes.

1. Add new interface, add_scrn_saver()/remove_scrn_saver(), to declare
loading/unloading of a screen saver.  The screen saver calls these
functions to notify syscons of loading/unloading events.

It was possible to load multiple savers each of which will try to
remember the previous saver in a local variable (`old_saver'). The
scheme breaks easily if the user load two savers and unload them in a
wrong order; if the first saver is unloaded first, `old_saver' in the
second saver points to nowhere.

Now only one screen saver is allowed in memory at a time.

Soeren will be looking into this issue again later.  syscons is
becoming too heavy.  It's time to cut things down, rather than adding
more...

2. Make scrn_timer() to be the primary caller of the screen saver
(*current_saver)(). scintr(), scioctl() and ansi_put() update
`scrn_time_stamp' to indicate that they want to stop the screen saver.

There are three exceptions, however.

One is remove_scrn_saver() which need to stop the current screen saver
if it is running. To guard against scrn_timer() calling the saver during
this operation, `current_saver' is set to `none_saver' early.

The others are sccngetc() and sccncheckc(); they will unblank the
screen too.  When the kernel enters DDB (via the hot key or a
break point), the screen saver will be stopped by sccngetc().
However, we have a reentrancy problem here. If the system has been in
the middle of the screen saver...

(The screen saver reentrancy problem has always been with sccnputc()
and sccngetc() in the -current source. So, the new code is doing no
worse, I reckon.)

3. Use `mono_time' rather than `time'.

4. Make set_border() work for EGA and CGA in addition to VGA. Do
nothing for MDA.

Changes to the LKM screen saver modules will follow shortly.  YOU NEED
TO RECOMPILE BOTH SCREEN SAVERS AND KERNEL AS OF THESE CHANGES.

Reviewed by: sos and bde

2 files changed, 97 insertions, 37 deletions

diff --git a/sys/isa/syscons.c b/sys/isa/syscons.c
index 71dc2b0..31d2b26d 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 1.223 1997/07/09 14:10:19 brian Exp $
+ *  $Id: syscons.c,v 1.224 1997/07/14 03:36:50 yokota Exp $
  */
 
 #include "sc.h"
@@ -118,7 +118,7 @@ static  u_char      	nlkcnt = 0, clkcnt = 0, slkcnt = 0, alkcnt = 0;
 static  const u_int     n_fkey_tab = sizeof(fkey_tab) / sizeof(*fkey_tab);
 static  int     	delayed_next_scr = FALSE;
 static  long        	scrn_blank_time = 0;    /* screen saver timeout value */
-	int     	scrn_blanked = FALSE;   /* screen saver active flag */
+	int     	scrn_blanked = 0;       /* screen saver active flag */
 static  long       	scrn_time_stamp;
 	u_char      	scr_map[256];
 	u_char      	scr_rmap[256];
@@ -144,7 +144,7 @@ static  u_short 	mouse_or_mask[16] = {
 			};
 
 static void    		none_saver(int blank) { }
-void    		(*current_saver)(int blank) = none_saver;
+static void    		(*current_saver)(int blank) = none_saver;
 int  			(*sc_user_ioctl)(dev_t dev, int cmd, caddr_t data,
 					 int flag, struct proc *p) = NULL;
 
@@ -192,6 +192,7 @@ static scr_stat *alloc_scp(void);
 static void init_scp(scr_stat *scp);
 static int get_scr_num(void);
 static timeout_t scrn_timer;
+static void stop_scrn_saver(void (*saver)(int));
 static void clear_screen(scr_stat *scp);
 static int switch_scr(scr_stat *scp, u_int next_scr);
 static void exchange_scr(void);
@@ -821,11 +822,7 @@ scintr(int unit)
     u_char *cp;
 
     /* make screensaver happy */
-    scrn_time_stamp = time.tv_sec;
-    if (scrn_blanked) {
-	(*current_saver)(FALSE);
-	mark_all(cur_console);
-    }
+    scrn_time_stamp = mono_time.tv_sec;
 
     /* 
      * Loop while there is still input to get from the keyboard.
@@ -919,11 +916,9 @@ scioctl(dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
     case CONS_BLANKTIME:    	/* set screen saver timeout (0 = no saver) */
 	if (*(int *)data < 0)
             return EINVAL;
-	scrn_blank_time = *(int*)data;
-	if ((scrn_blank_time == 0) && scrn_blanked) {
-	    (*current_saver)(FALSE);
-	    mark_all(cur_console);
-	}
+	scrn_blank_time = *(int *)data;
+	if (scrn_blank_time == 0)
+	    scrn_time_stamp = mono_time.tv_sec;
 	return 0;
 
     case CONS_CURSORTYPE:   	/* set cursor type blink/noblink */
@@ -1089,11 +1084,7 @@ scioctl(dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
 	    return EINVAL;
 	}
 	/* make screensaver happy */
-	scrn_time_stamp = time.tv_sec;
-	if (scrn_blanked) {
-	    (*current_saver)(FALSE);
-	    mark_all(cur_console);
-	}
+	scrn_time_stamp = mono_time.tv_sec;
 	return 0;
     }
 
@@ -1363,8 +1354,6 @@ scioctl(dev_t dev, int cmd, caddr_t data, int flag, struct proc *p)
 	return 0;
 
     case KDSBORDER:     	/* set border color of this (virtual) console */
-	if (!crtc_vga)
-	    return ENXIO;
 	scp->border = *data;
 	if (scp == cur_console)
 	    set_border(scp->border);
@@ -1691,8 +1680,20 @@ sccnputc(dev_t dev, int c)
 int
 sccngetc(dev_t dev)
 {
-    int s = spltty();       /* block scintr while we poll */
-    int c = scgetc(SCGETC_CN);
+    int s = spltty();	/* block scintr and scrn_timer while we poll */
+    int c;
+
+    /* 
+     * Stop the screen saver if necessary.
+     * What if we have been running in the screen saver code... XXX
+     */
+    if (scrn_blanked > 0)
+        stop_scrn_saver(current_saver);
+
+    c = scgetc(SCGETC_CN);
+
+    /* make sure the screen saver won't be activated soon */
+    scrn_time_stamp = mono_time.tv_sec;
     splx(s);
     return(c);
 }
@@ -1703,7 +1704,11 @@ sccncheckc(dev_t dev)
     int c, s;
 
     s = spltty();
+    if (scrn_blanked > 0)
+        stop_scrn_saver(current_saver);
     c = scgetc(SCGETC_CN | SCGETC_NONBLOCK);
+    if (c != NOKEY)
+        scrn_time_stamp = mono_time.tv_sec;
     splx(s);
     return(c == NOKEY ? -1 : c);	/* c == -1 can't happen */
 }
@@ -1766,7 +1771,12 @@ scrn_timer(void *arg)
 	return;
     }
 
-    if (!scrn_blanked) {
+    /* should we stop the screen saver? */
+    if (mono_time.tv_sec <= scrn_time_stamp + scrn_blank_time)
+	if (scrn_blanked > 0)
+            stop_scrn_saver(current_saver);
+
+    if (scrn_blanked <= 0) {
 	/* update screen image */
 	if (scp->start <= scp->end) {
 	    sc_bcopy(scp->scr_buf + scp->start, Crtat + scp->start,
@@ -1827,12 +1837,52 @@ scrn_timer(void *arg)
 	scp->end = 0;
 	scp->start = scp->xsize*scp->ysize;
     }
-    if (scrn_blank_time && (time.tv_sec > scrn_time_stamp+scrn_blank_time))
+
+    /* should we activate the screen saver? */
+    if ((scrn_blank_time != 0) 
+	    && (mono_time.tv_sec > scrn_time_stamp + scrn_blank_time))
 	(*current_saver)(TRUE);
+
     timeout(scrn_timer, NULL, hz / 25);
     splx(s);
 }
 
+int
+add_scrn_saver(void (*this_saver)(int))
+{
+    if (current_saver != none_saver)
+	return EBUSY;
+    current_saver = this_saver;
+    return 0;
+}
+
+int
+remove_scrn_saver(void (*this_saver)(int))
+{
+    if (current_saver != this_saver)
+	return EINVAL;
+
+    /*
+     * In order to prevent `current_saver' from being called by
+     * the timeout routine `scrn_timer()' while we manipulate 
+     * the saver list, we shall set `current_saver' to `none_saver' 
+     * before stopping the current saver, rather than blocking by `splXX()'.
+     */
+    current_saver = none_saver;
+    if (scrn_blanked > 0)
+        stop_scrn_saver(this_saver);
+
+    return 0;
+}
+
+static void
+stop_scrn_saver(void (*saver)(int))
+{
+    (*saver)(FALSE);
+    scrn_time_stamp = mono_time.tv_sec;
+    mark_all(cur_console);
+}
+
 static void
 clear_screen(scr_stat *scp)
 {
@@ -2367,7 +2417,7 @@ scan_esc(scr_stat *scp, u_char c)
 	    break;
 
 	case 'A':   /* set display border color */
-	    if ((scp->term.num_param == 1) && crtc_vga) {
+	    if (scp->term.num_param == 1) {
 		scp->border=scp->term.param[0] & 0xff;
 		if (scp == cur_console)
 		    set_border(scp->border);
@@ -2456,13 +2506,9 @@ ansi_put(scr_stat *scp, u_char *buf, int len)
     u_char *ptr = buf;
 
     /* make screensaver happy */
-    if (scp == cur_console) {
-	scrn_time_stamp = time.tv_sec;
-	if (scrn_blanked) {
-	    (*current_saver)(FALSE);
-	    mark_all(scp);
-	}
-    }
+    if (scp == cur_console)
+	scrn_time_stamp = mono_time.tv_sec;
+
     write_in_progress++;
 outloop:
     if (scp->term.esc) {
@@ -3466,10 +3512,22 @@ setup_mode:
 void
 set_border(u_char color)
 {
-    inb(crtc_addr+6);               /* reset flip-flop */
-    outb(ATC, 0x11); outb(ATC, color);
-    inb(crtc_addr+6);               /* reset flip-flop */
-    outb(ATC, 0x20);                /* enable Palette */
+    switch (crtc_type) {
+    case KD_EGA:
+    case KD_VGA:
+        inb(crtc_addr + 6);		/* reset flip-flop */
+        outb(ATC, 0x11); outb(ATC, color);
+        inb(crtc_addr + 6);		/* reset flip-flop */
+        outb(ATC, 0x20);		/* enable Palette */
+	break;
+    case KD_CGA:
+	outb(crtc_addr + 5, color & 0x0f); /* color select register */
+	break;
+    case KD_MONO:
+    case KD_HERCULES:
+    default:
+	break;
+    }
 }
 
 static void
diff --git a/sys/isa/syscons.h b/sys/isa/syscons.h
index 7d46410..78703f7 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 1.29 1997/05/15 05:43:59 yokota Exp $
+ *	$Id: syscons.h,v 1.30 1997/06/29 15:11:40 yokota Exp $
  */
 
 #ifndef _I386_ISA_SYSCONS_H_
@@ -196,5 +196,7 @@ void set_border(u_char color);
 void set_mode(scr_stat *scp);
 void copy_font(int operation, int font_type, char* font_image);
 void load_palette(char *palette);
+int add_scrn_saver(void (*this)(int));
+int remove_scrn_saver(void (*this)(int));
 
 #endif /* !_I386_ISA_SYSCONS_H_ */