patches to optionally clear the screen during boot.

[christos%zoulas.com@localhost (Christos Zoulas)]

Currently the x86 boot code clears the screen which seems un-unix like
and unnecessary. This patch makes the behavior optional via boot.conf.
Anon Ymous wrote it. Ok to commit?

christos

Index: boot/boot2.c
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/boot/boot2.c,v
retrieving revision 1.40
diff -u -r1.40 boot2.c
--- boot/boot2.c        25 Nov 2008 13:23:54 -0000      1.40
+++ boot/boot2.c        13 Dec 2008 20:55:22 -0000
@@ -239,6 +239,9 @@
 void
 print_banner(void)
 {
+       if (bootconf.clear)
+               clear_pc_screen();
+
 #ifndef SMALL
        int n;
        if (bootconf.banner[0]) {
@@ -271,7 +274,6 @@
        char c;
 
        twiddle_toggle = 1;     /* no twiddling until we're ready */
-       printf("\f");           /* clear screen (hopefully) */
 
        initio(boot_params.bp_consdev);
 
Index: dosboot/main.c
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/dosboot/main.c,v
retrieving revision 1.24
diff -u -r1.24 main.c
--- dosboot/main.c      26 Sep 2008 14:12:49 -0000      1.24
+++ dosboot/main.c      13 Dec 2008 20:34:41 -0000
@@ -216,6 +216,8 @@
        int extmem = getextmem();
        char *s = "";
 
+       clear_pc_screen();
+
 #ifdef XMS
        u_long xmsmem;
        if (getextmem1() == 0 && (xmsmem = checkxms()) != 0) {
Index: lib/bootmenu.c
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/lib/bootmenu.c,v
retrieving revision 1.1
diff -u -r1.1 bootmenu.c
--- lib/bootmenu.c      25 Nov 2008 13:23:54 -0000      1.1
+++ lib/bootmenu.c      13 Dec 2008 20:49:52 -0000
@@ -81,6 +81,7 @@
  * default: the default menu option to use if Return is pressed
  * consdev: the console device to use
  * format: how menu choices are displayed: (a)utomatic, (n)umbers or (l)etters
+ * clear: whether to clear the screen or not
  *
  * Example boot.cfg file:
  * banner=Welcome to NetBSD
@@ -110,7 +111,10 @@
 
        /* automatically switch between letter and numbers on menu */
        bootconf.menuformat = MENUFORMAT_AUTO;
-
+#if 0
+       /* XXX - clear the screen by default? */
+       bootconf.clear = 1;
+#endif
        fd = open(BOOTCONF, 0);
        if (fd < 0)
                return;
@@ -214,6 +218,8 @@
                                bootconf.menuformat = MENUFORMAT_LETTER;
                                break;
                        }
+               } else if (!strncmp(key, "clear", 5)) {
+                       bootconf.clear = atoi(value) != 0;
                }
        }
        switch (bootconf.menuformat) {
Index: lib/bootmenu.h
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/lib/bootmenu.h,v
retrieving revision 1.1
diff -u -r1.1 bootmenu.h
--- lib/bootmenu.h      25 Nov 2008 13:23:54 -0000      1.1
+++ lib/bootmenu.h      13 Dec 2008 16:45:13 -0000
@@ -47,6 +47,7 @@
        int nummenu;                    /* Number of menu items */
        int timeout;                    /* Timeout in seconds */
        int menuformat;                 /* Print letters instead of numbers? */
+       int clear;                      /* Clear the screen? */
 } extern bootconf;
 
 #endif /* !_BOOTMENU_H */
Index: lib/libi386.h
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/lib/libi386.h,v
retrieving revision 1.27
diff -u -r1.27 libi386.h
--- lib/libi386.h       19 Nov 2008 12:36:41 -0000      1.27
+++ lib/libi386.h       13 Dec 2008 20:30:33 -0000
@@ -55,6 +55,7 @@
 void reboot(void);
 void gateA20(void);
 
+void clear_pc_screen(void);
 void initio(int);
 #define CONSDEV_PC 0
 #define CONSDEV_COM0 1
Index: lib/pcio.c
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/lib/pcio.c,v
retrieving revision 1.23
diff -u -r1.23 pcio.c
--- lib/pcio.c  21 May 2008 13:36:45 -0000      1.23
+++ lib/pcio.c  13 Dec 2008 20:59:25 -0000
@@ -87,6 +87,16 @@
 #endif
 
 void
+clear_pc_screen(void)
+{
+#ifdef SUPPORT_SERIAL
+       /* Clear the screen if we are on a glass tty. */
+       if (iodev == CONSDEV_PC)
+               conclr();
+#endif
+}
+
+void
 initio(int dev)
 {
 #ifdef SUPPORT_SERIAL
@@ -201,10 +211,6 @@
        conputc('\n');
        strncpy(btinfo_console.devname, iodev == CONSDEV_PC ? "pc" : "com", 16);
 
-       if (iodev == CONSDEV_PC) {
-               /* Clear screen if on a glass tty. */
-               conclr();
-       }
 #else /* !SUPPORT_SERIAL */
        btinfo_console.devname[0] = 'p';
        btinfo_console.devname[1] = 'c';
Index: netboot/main.c
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/netboot/main.c,v
retrieving revision 1.12
diff -u -r1.12 main.c
--- netboot/main.c      26 Sep 2008 14:12:50 -0000      1.12
+++ netboot/main.c      13 Dec 2008 20:35:59 -0000
@@ -76,6 +76,7 @@
 static void
 print_banner(void)
 {
+       clear_pc_screen();
 
        printf("\n"
               ">> %s, Revision %s (from NetBSD %s)\n"
Index: pxeboot/main.c
===================================================================
RCS file: /s/NetBSD/cvsroot/src/sys/arch/i386/stand/pxeboot/main.c,v
retrieving revision 1.16
diff -u -r1.16 main.c
--- pxeboot/main.c      25 Nov 2008 13:23:54 -0000      1.16
+++ pxeboot/main.c      13 Dec 2008 20:37:17 -0000
@@ -91,6 +91,9 @@
        int base = getbasemem();
        int ext = getextmem();
 
+       if (bootconf.clear)
+               clear_pc_screen();
+
        printf("\n"
               ">> NetBSD/x86 PXE boot, Revision %s (from NetBSD %s)\n"
               ">> Memory: %d/%d k\n",