[src/trunk]: src/sys/dev/wscons make vcons_putchar_buffer() return a flag ind...

[macallan <macallan%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7ceb6cb271fd
branches:  trunk
changeset: 373506:7ceb6cb271fd
user:      macallan <macallan%NetBSD.org@localhost>
date:      Tue Feb 14 08:14:02 2023 +0000

description:
make vcons_putchar_buffer() return a flag indicating if anything actually
changed, skip the actual drawing op if nothing did

diffstat:

 sys/dev/wscons/wsdisplay_vcons.c |  27 ++++++++++++++++-----------
 1 files changed, 16 insertions(+), 11 deletions(-)

diffs (85 lines):

diff -r fb97f74e2d60 -r 7ceb6cb271fd sys/dev/wscons/wsdisplay_vcons.c
--- a/sys/dev/wscons/wsdisplay_vcons.c  Mon Feb 13 23:14:21 2023 +0000
+++ b/sys/dev/wscons/wsdisplay_vcons.c  Tue Feb 14 08:14:02 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: wsdisplay_vcons.c,v 1.64 2022/07/18 11:09:22 martin Exp $ */
+/*     $NetBSD: wsdisplay_vcons.c,v 1.65 2023/02/14 08:14:02 macallan Exp $ */
 
 /*-
  * Copyright (c) 2005, 2006 Michael Lorenz
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: wsdisplay_vcons.c,v 1.64 2022/07/18 11:09:22 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: wsdisplay_vcons.c,v 1.65 2023/02/14 08:14:02 macallan Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -121,7 +121,7 @@
 static void vcons_erasecols_buffer(void *, int, int, int, long);
 static void vcons_copyrows_buffer(void *, int, int, int);
 static void vcons_eraserows_buffer(void *, int, int, long);
-static void vcons_putchar_buffer(void *, int, int, u_int, long);
+static int vcons_putchar_buffer(void *, int, int, u_int, long);
 
 /*
  * actual wrapper methods which call both the _buffer ones above and the
@@ -1237,22 +1237,25 @@
        vcons_unlock(scr);
 }
 
-static void
+static int
 vcons_putchar_buffer(void *cookie, int row, int col, u_int c, long attr)
 {
        struct rasops_info *ri = cookie;
        struct vcons_screen *scr = ri->ri_hw;
        int offset = vcons_offset_to_zero(scr);
-       int pos;
+       int pos, ret = 0;
 
        if ((row >= 0) && (row < ri->ri_rows) && (col >= 0) &&
             (col < ri->ri_cols)) {
                pos = col + row * ri->ri_cols;
+               ret = (scr->scr_attrs[pos + offset] != attr) ||
+                     (scr->scr_chars[pos + offset] != c);
                scr->scr_attrs[pos + offset] = attr;
                scr->scr_chars[pos + offset] = c;
        }
 
-       vcons_dirty(scr);
+       if (ret) vcons_dirty(scr);
+       return ret;
 }
 
 #ifdef VCONS_DRAW_INTR
@@ -1282,8 +1285,9 @@
 {
        struct rasops_info *ri = cookie;
        struct vcons_screen *scr = ri->ri_hw;
-
-       vcons_putchar_buffer(cookie, row, col, c, attr);
+       int need_draw;
+       
+       need_draw = vcons_putchar_buffer(cookie, row, col, c, attr);
 
        if (vcons_use_intr(scr))
                return;
@@ -1291,12 +1295,13 @@
        vcons_lock(scr);
        if (SCREEN_IS_VISIBLE(scr) && SCREEN_CAN_DRAW(scr)) {
 #ifdef VCONS_DRAW_INTR
-               vcons_putchar_cached(cookie, row, col, c, attr);
+               if (need_draw) vcons_putchar_cached(cookie, row, col, c, attr);
 #else
                if (row == ri->ri_crow && col == ri->ri_ccol) {
                        ri->ri_flg &= ~RI_CURSOR;
-               }
-               scr->putchar(cookie, row, col, c, attr);
+                       scr->putchar(cookie, row, col, c, attr);
+               } else if (need_draw)
+                       scr->putchar(cookie, row, col, c, attr);
 #endif
        }
        vcons_unlock(scr);