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.

5 files changed, 63 insertions, 30 deletions

diff --git a/sys/dev/fb/vesa.c b/sys/dev/fb/vesa.c
index baebe85..2602440 100644
--- a/sys/dev/fb/vesa.c
+++ b/sys/dev/fb/vesa.c
@@ -165,7 +165,9 @@ static int int10_set_mode(int mode);
 static int vesa_bios_post(void);
 static int vesa_bios_get_mode(int mode, struct vesa_mode *vmode);
 static int vesa_bios_set_mode(int mode);
+#if 0
 static int vesa_bios_get_dac(void);
+#endif
 static int vesa_bios_set_dac(int bits);
 static int vesa_bios_save_palette(int start, int colors, u_char *palette,
 				  int bits);
@@ -318,6 +320,7 @@ vesa_bios_set_mode(int mode)
 	return (regs.R_AX != 0x004f);
 }
 
+#if 0
 static int
 vesa_bios_get_dac(void)
 {
@@ -334,6 +337,7 @@ vesa_bios_get_dac(void)
 
 	return (regs.R_BH);
 }
+#endif
 
 static int
 vesa_bios_set_dac(int bits)
@@ -1198,6 +1202,10 @@ vesa_set_mode(video_adapter_t *adp, int mode)
 	if (VESA_MODE(adp->va_mode)) {
 		if (!VESA_MODE(mode) &&
 		    (*prevvidsw->get_info)(adp, mode, &info) == 0) {
+			if ((adp->va_flags & V_ADP_DAC8) != 0) {
+				vesa_bios_set_dac(6);
+				adp->va_flags &= ~V_ADP_DAC8;
+			}
 			int10_set_mode(adp->va_initial_bios_mode);
 			if (adp->va_info.vi_flags & V_INFO_LINEAR)
 				pmap_unmapdev(adp->va_buffer,
@@ -1228,8 +1236,14 @@ vesa_set_mode(video_adapter_t *adp, int mode)
 	if (vesa_bios_set_mode(mode | ((info.vi_flags & V_INFO_LINEAR) ? 0x4000 : 0)))
 		return (1);
 
-	if ((vesa_adp_info->v_flags & V_DAC8) != 0)
-		vesa_bios_set_dac(8);
+	/* Palette format is reset by the above VBE function call. */
+	adp->va_flags &= ~V_ADP_DAC8;
+
+	if ((vesa_adp_info->v_flags & V_DAC8) != 0 &&
+	    (info.vi_flags & V_INFO_GRAPHICS) != 0 &&
+	    (info.vi_flags & V_INFO_NONVGA) != 0 &&
+	    vesa_bios_set_dac(8) > 6)
+		adp->va_flags |= V_ADP_DAC8;
 
 	if (adp->va_info.vi_flags & V_INFO_LINEAR)
 		pmap_unmapdev(adp->va_buffer, adp->va_buffer_size);
@@ -1308,10 +1322,10 @@ vesa_save_palette(video_adapter_t *adp, u_char *palette)
 {
 	int bits;
 
-	if (adp == vesa_adp && VESA_MODE(adp->va_mode)) {
-		bits = vesa_bios_get_dac();
-		if ((adp->va_info.vi_flags & V_INFO_NONVGA) != 0 || bits > 6)
-			return (vesa_bios_save_palette(0, 256, palette, bits));
+	if (adp == vesa_adp && VESA_MODE(adp->va_mode) &&
+	    (adp->va_info.vi_flags & V_INFO_NONVGA) != 0) {
+		bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
+		return (vesa_bios_save_palette(0, 256, palette, bits));
 	}
 
 	return ((*prevvidsw->save_palette)(adp, palette));
@@ -1322,10 +1336,10 @@ vesa_load_palette(video_adapter_t *adp, u_char *palette)
 {
 	int bits;
 
-	if (adp == vesa_adp && VESA_MODE(adp->va_mode)) {
-		bits = vesa_bios_get_dac();
-		if ((adp->va_info.vi_flags & V_INFO_NONVGA) != 0 || bits > 6)
-			return (vesa_bios_load_palette(0, 256, palette, bits));
+	if (adp == vesa_adp && VESA_MODE(adp->va_mode) &&
+	    (adp->va_info.vi_flags & V_INFO_NONVGA) != 0) {
+		bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
+		return (vesa_bios_load_palette(0, 256, palette, bits));
 	}
 
 	return ((*prevvidsw->load_palette)(adp, palette));
@@ -1530,10 +1544,10 @@ get_palette(video_adapter_t *adp, int base, int count,
 		return (1);
 	if (!VESA_MODE(adp->va_mode))
 		return (1);
-	bits = vesa_bios_get_dac();
-	if ((adp->va_info.vi_flags & V_INFO_NONVGA) == 0 && bits <= 6)
+	if ((adp->va_info.vi_flags & V_INFO_NONVGA) == 0)
 		return (1);
 
+	bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
 	r = malloc(count * 3, M_DEVBUF, M_WAITOK);
 	g = r + count;
 	b = g + count;
@@ -1568,10 +1582,10 @@ set_palette(video_adapter_t *adp, int base, int count,
 		return (1);
 	if (!VESA_MODE(adp->va_mode))
 		return (1);
-	bits = vesa_bios_get_dac();
-	if ((adp->va_info.vi_flags & V_INFO_NONVGA) == 0 && bits <= 6)
+	if ((adp->va_info.vi_flags & V_INFO_NONVGA) == 0)
 		return (1);
 
+	bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
 	r = malloc(count * 3, M_DEVBUF, M_WAITOK);
 	g = r + count;
 	b = g + count;
@@ -1789,7 +1803,6 @@ vesa_unload(void)
 {
 	u_char palette[256*3];
 	int error;
-	int bits;
 	int s;
 
 	/* if the adapter is currently in a VESA mode, don't unload */
@@ -1803,15 +1816,11 @@ vesa_unload(void)
 	s = spltty();
 	if ((error = vesa_unload_ioctl()) == 0) {
 		if (vesa_adp != NULL) {
-			if (vesa_adp_info->v_flags & V_DAC8)  {
-				bits = vesa_bios_get_dac();
-				if (bits > 6) {
-					vesa_bios_save_palette(0, 256,
-							       palette, bits);
-					vesa_bios_set_dac(6);
-					vesa_bios_load_palette(0, 256,
-							       palette, 6);
-				}
+			if ((vesa_adp->va_flags & V_ADP_DAC8) != 0) {
+				vesa_bios_save_palette(0, 256, palette, 8);
+				vesa_bios_set_dac(6);
+				vesa_adp->va_flags &= ~V_ADP_DAC8;
+				vesa_bios_load_palette(0, 256, palette, 6);
 			}
 			vesa_adp->va_flags &= ~V_ADP_VESA;
 			vidsw[vesa_adp->va_index] = prevvidsw;
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
diff --git a/sys/sys/fbio.h b/sys/sys/fbio.h
index 415ad96..5745182 100644
--- a/sys/sys/fbio.h
+++ b/sys/sys/fbio.h
@@ -332,6 +332,7 @@ struct video_adapter {
 #define V_ADP_INITIALIZED (1 << 17)
 #define V_ADP_REGISTERED (1 << 18)
 #define V_ADP_ATTACHED	(1 << 19)
+#define	V_ADP_DAC8	(1 << 20)
     vm_offset_t		va_io_base;
     int			va_io_size;
     vm_offset_t		va_crtc_addr;