viafb: rework color checking

Make color checking a bit more tolerant in what values it allows and more
fine grained to later support 15 and 30 bits formats.  It splits the
filling of the color information in var to a seperate function and sets
some color related values in var that where previously untouched.

This could be a bug fix but at least I don't know any applications that
was fooled by not correctly setting the fields in var.  At least no
regressions are expected.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: Scott Fang <ScottFang@viatech.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/via/hw.c

@@ -2622,36 +2622,6 @@ void viafb_fill_var_timing_info(struct fb_var_screeninfo *var, int refresh,
 	}
 
 	crt_reg = crt_timing[index].crtc;
-	switch (var->bits_per_pixel) {
-	case 8:
-		var->red.offset = 0;
-		var->green.offset = 0;
-		var->blue.offset = 0;
-		var->red.length = 6;
-		var->green.length = 6;
-		var->blue.length = 6;
-		break;
-	case 16:
-		var->red.offset = 11;
-		var->green.offset = 5;
-		var->blue.offset = 0;
-		var->red.length = 5;
-		var->green.length = 6;
-		var->blue.length = 5;
-		break;
-	case 32:
-		var->red.offset = 16;
-		var->green.offset = 8;
-		var->blue.offset = 0;
-		var->red.length = 8;
-		var->green.length = 8;
-		var->blue.length = 8;
-		break;
-	default:
-		/* never happed, put here to keep consistent */
-		break;
-	}
-
 	var->pixclock = viafb_get_pixclock(var->xres, var->yres, refresh);
 	var->left_margin =
 	    crt_reg.hor_total - (crt_reg.hor_sync_start + crt_reg.hor_sync_end);

drivers/video/via/viafbdev.c

@@ -60,6 +60,47 @@ static int viafb_pan_display(struct fb_var_screeninfo *var,
 static struct fb_ops viafb_ops;
 
 
+static void viafb_fill_var_color_info(struct fb_var_screeninfo *var, u8 depth)
+{
+	var->grayscale = 0;
+	var->red.msb_right = 0;
+	var->green.msb_right = 0;
+	var->blue.msb_right = 0;
+	var->transp.offset = 0;
+	var->transp.length = 0;
+	var->transp.msb_right = 0;
+	var->nonstd = 0;
+	switch (depth) {
+	case 8:
+		var->bits_per_pixel = 8;
+		var->red.offset = 0;
+		var->green.offset = 0;
+		var->blue.offset = 0;
+		var->red.length = 6;
+		var->green.length = 6;
+		var->blue.length = 6;
+		break;
+	case 16:
+		var->bits_per_pixel = 16;
+		var->red.offset = 11;
+		var->green.offset = 5;
+		var->blue.offset = 0;
+		var->red.length = 5;
+		var->green.length = 6;
+		var->blue.length = 5;
+		break;
+	case 24:
+		var->bits_per_pixel = 32;
+		var->red.offset = 16;
+		var->green.offset = 8;
+		var->blue.offset = 0;
+		var->red.length = 8;
+		var->green.length = 8;
+		var->blue.length = 8;
+		break;
+	}
+}
+
 static void viafb_update_fix(struct fb_info *info)
 {
 	u32 bpp = info->var.bits_per_pixel;
@@ -81,6 +122,7 @@ static void viafb_setup_fixinfo(struct fb_fix_screeninfo *fix,
 
 	fix->type = FB_TYPE_PACKED_PIXELS;
 	fix->type_aux = 0;
+	fix->visual = FB_VISUAL_TRUECOLOR;
 
 	fix->xpanstep = fix->ywrapstep = 0;
 	fix->ypanstep = 1;
@@ -103,7 +145,7 @@ static int viafb_release(struct fb_info *info, int user)
 static int viafb_check_var(struct fb_var_screeninfo *var,
 	struct fb_info *info)
 {
-	int htotal, vtotal;
+	int htotal, vtotal, depth;
 	struct VideoModeTable *vmode_entry;
 	struct viafb_par *ppar = info->par;
 	u32 long_refresh;
@@ -122,13 +164,22 @@ static int viafb_check_var(struct fb_var_screeninfo *var,
 		return -EINVAL;
 	}
 
-	if (24 == var->bits_per_pixel)
-		var->bits_per_pixel = 32;
+	depth = fb_get_color_depth(var, &info->fix);
+	if (!depth)
+		depth = var->bits_per_pixel;
 
-	if (var->bits_per_pixel != 8 && var->bits_per_pixel != 16 &&
-		var->bits_per_pixel != 32)
+	if (depth < 0 || depth > 32)
 		return -EINVAL;
+	else if (!depth)
+		depth = 24;
+	else if (depth <= 8)
+		depth = 8;
+	else if (depth <= 16)
+		depth = 16;
+	else
+		depth = 24;
 
+	viafb_fill_var_color_info(var, depth);
 	if ((var->xres_virtual * (var->bits_per_pixel >> 3)) & 0x1F)
 		/*32 pixel alignment */
 		var->xres_virtual = (var->xres_virtual + 31) & ~31;