Yet another attempt to make palette loading more safer:

- Add a separate palette data for 8-bit DAC mode when SC_PIXEL_MODE is set
and fill it up with default gray-scale palette data for text.  Now we don't
have to set `hint.sc.0.vesa_mode' to get the default palette data.
- Add a new adapter flag, V_ADP_DAC8 to track whether the controller is
using 8-bit palette format and load correct palette when switching modes.
- Set 8-bit DAC mode only for non-VGA compatible graphics mode.

3 files changed, 29 insertions, 6 deletions

diff --git a/sys/dev/syscons/scvidctl.c b/sys/dev/syscons/scvidctl.c
index f973169..d4f1725 100644
--- a/sys/dev/syscons/scvidctl.c
+++ b/sys/dev/syscons/scvidctl.c
@@ -725,6 +725,11 @@ sc_vid_ioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
 #endif
 
 #ifndef SC_NO_PALETTE_LOADING
+#ifdef SC_PIXEL_MODE
+	    if ((adp->va_flags & V_ADP_DAC8) != 0)
+		vidd_load_palette(adp, scp->sc->palette2);
+	    else
+#endif
 	    vidd_load_palette(adp, scp->sc->palette);
 #endif
 
@@ -782,7 +787,10 @@ sc_vid_ioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
 	    if (scp == scp->sc->cur_scp) {
 		set_mode(scp);
 #ifndef SC_NO_PALETTE_LOADING
-		vidd_load_palette(adp, scp->sc->palette);
+		if ((adp->va_flags & V_ADP_DAC8) != 0)
+		    vidd_load_palette(adp, scp->sc->palette2);
+		else
+		    vidd_load_palette(adp, scp->sc->palette);
 #endif
 	    }
 	    sc_clear_screen(scp);
diff --git a/sys/dev/syscons/syscons.c b/sys/dev/syscons/syscons.c
index f50d686..88bf019 100644
--- a/sys/dev/syscons/syscons.c
+++ b/sys/dev/syscons/syscons.c
@@ -414,9 +414,6 @@ sc_attach_unit(int unit, int flags)
 #endif
 	    sc_set_graphics_mode(scp, NULL, vmode);
 	    sc_set_pixel_mode(scp, NULL, 0, 0, 16, 8);
-#ifndef SC_NO_PALETTE_LOADING
-	    vidd_save_palette(sc->adp, sc->palette);
-#endif
 	    sc->initial_mode = vmode;
 #ifdef DEV_SPLASH
 	    /* put up the splash again! */
@@ -2090,6 +2087,11 @@ restore_scrn_saver_mode(scr_stat *scp, int changemode)
     }
     if (set_mode(scp) == 0) {
 #ifndef SC_NO_PALETTE_LOADING
+#ifdef SC_PIXEL_MODE
+	if ((scp->sc->adp->va_flags & V_ADP_DAC8) != 0)
+	    vidd_load_palette(scp->sc->adp, scp->sc->palette2);
+	else
+#endif
 	vidd_load_palette(scp->sc->adp, scp->sc->palette);
 #endif
 	--scrn_blanked;
@@ -2493,8 +2495,14 @@ exchange_scr(sc_softc_t *sc)
     if (!ISGRAPHSC(scp))
 	sc_set_cursor_image(scp);
 #ifndef SC_NO_PALETTE_LOADING
-    if (ISGRAPHSC(sc->old_scp))
+    if (ISGRAPHSC(sc->old_scp)) {
+#ifdef SC_PIXEL_MODE
+	if ((sc->adp->va_flags & V_ADP_DAC8) != 0)
+	    vidd_load_palette(sc->adp, sc->palette2);
+	else
+#endif
 	vidd_load_palette(sc->adp, sc->palette);
+    }
 #endif
     sc_set_border(scp, scp->border);
 
@@ -2843,6 +2851,10 @@ scinit(int unit, int flags)
 
 #ifndef SC_NO_PALETTE_LOADING
 	vidd_save_palette(sc->adp, sc->palette);
+#ifdef SC_PIXEL_MODE
+	for (i = 0; i < sizeof(sc->palette2); i++)
+		sc->palette2[i] = i / 3;
+#endif
 #endif
 
 #ifdef DEV_SPLASH
diff --git a/sys/dev/syscons/syscons.h b/sys/dev/syscons/syscons.h
index 2f05755..ee38089 100644
--- a/sys/dev/syscons/syscons.h
+++ b/sys/dev/syscons/syscons.h
@@ -245,7 +245,10 @@ typedef struct sc_softc {
 #endif
 
 #ifndef SC_NO_PALETTE_LOADING
-	u_char        	palette[256*3];
+	u_char		palette[256 * 3];
+#ifdef SC_PIXEL_MODE
+	u_char		palette2[256 * 3];
+#endif
 #endif
 
 #ifndef SC_NO_FONT_LOADING