Disabled clearing screen in tty driver, started console printing after an

initial 1-line scroll at last line. If clearing screen in trailer of boot
monitor is disabled, all previous boot monitor and console messages are
preserved on rebooting.

All that's needed now is a scrollback buffer to see all old messages..
(Even from the boot monitor, bios, previous boots...)

diff --git a/drivers/tty/console.c b/drivers/tty/console.c
index 0f98a1416861f487a51b357b157f24ef3d569289..7cb74157db68e8cbcc3f6c37b2323d63cedfc839 100644 (file)
--- a/drivers/tty/console.c
+++ b/drivers/tty/console.c
@@ -40,6 +40,7 @@
 #define C_6845         0x3D4   /* port for 6845 color */
 #define INDEX              0   /* 6845's index register */
 #define DATA               1   /* 6845's data register */
+#define STATUS             6   /* 6845's status register */
 #define VID_ORG           12   /* 6845's origin register */
 #define CURSOR            14   /* 6845's cursor register */
 
@@ -120,6 +121,7 @@ FORWARD _PROTOTYPE( void flush, (console_t *cons)                   );
 FORWARD _PROTOTYPE( void parse_escape, (console_t *cons, int c)                );
 FORWARD _PROTOTYPE( void scroll_screen, (console_t *cons, int dir)     );
 FORWARD _PROTOTYPE( void set_6845, (int reg, unsigned val)             );
+FORWARD _PROTOTYPE( void get_6845, (int reg, unsigned *val)            );
 FORWARD _PROTOTYPE( void stop_beep, (timer_t *tmrp)                            );
 FORWARD _PROTOTYPE( void cons_org0, (void)                             );
 FORWARD _PROTOTYPE( int ga_program, (struct sequence *seq)             );
@@ -706,6 +708,22 @@ unsigned val;                      /* 16-bit value to set it to */
   sys_voutb(char_out, 4);                      /* do actual output */
 }
 
+/*===========================================================================*
+ *                             get_6845                                     *
+ *===========================================================================*/
+PRIVATE void get_6845(reg, val)
+int reg;                       /* which register pair to set */
+unsigned *val;                 /* 16-bit value to set it to */
+{
+  char v1, v2;
+/* Get a register pair inside the 6845.  */
+  sys_outb(vid_port + INDEX, reg); 
+  sys_inb(vid_port + DATA, &v1); 
+  sys_outb(vid_port + INDEX, reg+1); 
+  sys_inb(vid_port + DATA, &v2); 
+  *val = (v1 << 8) | v2;
+}
+
 
 /*===========================================================================*
  *                             beep                                         *
@@ -771,9 +789,9 @@ tty_t *tp;
   u16_t bios_columns, bios_crtbase, bios_fontlines;
   u8_t bios_rows;
   int line;
-  unsigned page_size;
   int s;
   static int vdu_initialized = 0;
+  unsigned page_size;
 
   /* Associate console and TTY. */
   line = tp - &tty_table[0];
@@ -838,9 +856,19 @@ tty_t *tp;
   cons->c_cur = cons->c_org = cons->c_start;
   cons->c_attr = cons->c_blank = BLANK_COLOR;
 
-  /* Clear the screen. */
-  blank_color = BLANK_COLOR;
-  mem_vid_copy(BLANK_MEM, cons->c_start, scr_size);
+  if(line != 0) {
+        /* Clear the non-console vtys. */
+       blank_color = BLANK_COLOR;
+       mem_vid_copy(BLANK_MEM, cons->c_start, scr_size);
+  } else {
+       int i, n;
+       /* Set the cursor of the console vty at the bottom. c_cur
+        * is updated automatically later.
+        */
+       scroll_screen(cons, SCROLL_UP);
+       cons->c_row = scr_lines-1;
+       cons->c_column = 0;
+  }
   select_console(0);
   cons_ioctl(tp);
 }