video: fbdev: Check Standard Timing against DMT

Add the VESA Display Monitor Timing (DMT) table.
During parsing of Standard Timings, it compare the 2 byte STD code
with DMT to see what the VESA mode should be. If there is no entry
in the vesa_modes table or no match found, it fallsback to the
GTF timings.

Signed-off-by: David Ung <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/video/fbdev/core/fbmon.c

···
 static int get_std_timing(unsigned char *block, struct fb_videomode *mode,
 		int ver, int rev)
 {
-	int xres, yres = 0, refresh, ratio, i;
+	int i;
 
-	xres = (block[0] + 31) * 8;
-	if (xres <= 256)
-		return 0;
-
-	ratio = (block[1] & 0xc0) >> 6;
-	switch (ratio) {
-	case 0:
-		/* in EDID 1.3 the meaning of 0 changed to 16:10 (prior 1:1) */
-		if (ver < 1 || (ver == 1 && rev < 3))
-			yres = xres;
-		else
-			yres = (xres * 10)/16;
-		break;
-	case 1:
-		yres = (xres * 3)/4;
-		break;
-	case 2:
-		yres = (xres * 4)/5;
-		break;
-	case 3:
-		yres = (xres * 9)/16;
-		break;
+	for (i = 0; i < DMT_SIZE; i++) {
+		u32 std_2byte_code = block[0] << 8 | block[1];
+		if (std_2byte_code == dmt_modes[i].std_2byte_code)
+			break;
 	}
-	refresh = (block[1] & 0x3f) + 60;
 
-	DPRINTK("      %dx%d@%dHz\n", xres, yres, refresh);
-	for (i = 0; i < VESA_MODEDB_SIZE; i++) {
-		if (vesa_modes[i].xres == xres &&
-		    vesa_modes[i].yres == yres &&
-		    vesa_modes[i].refresh == refresh) {
-			*mode = vesa_modes[i];
-			mode->flag |= FB_MODE_IS_STANDARD;
-			return 1;
+	if (i < DMT_SIZE && dmt_modes[i].mode) {
+		/* DMT mode found */
+		*mode = *dmt_modes[i].mode;
+		mode->flag |= FB_MODE_IS_STANDARD;
+		DPRINTK("        DMT id=%d\n", dmt_modes[i].dmt_id);
+
+	} else {
+		int xres, yres = 0, refresh, ratio;
+
+		xres = (block[0] + 31) * 8;
+		if (xres <= 256)
+			return 0;
+
+		ratio = (block[1] & 0xc0) >> 6;
+		switch (ratio) {
+		case 0:
+			/* in EDID 1.3 the meaning of 0 changed to 16:10 (prior 1:1) */
+			if (ver < 1 || (ver == 1 && rev < 3))
+				yres = xres;
+			else
+				yres = (xres * 10)/16;
+			break;
+		case 1:
+			yres = (xres * 3)/4;
+			break;
+		case 2:
+			yres = (xres * 4)/5;
+			break;
+		case 3:
+			yres = (xres * 9)/16;
+			break;
 		}
+		refresh = (block[1] & 0x3f) + 60;
+		DPRINTK("      %dx%d@%dHz\n", xres, yres, refresh);
+
+		calc_mode_timings(xres, yres, refresh, mode);
 	}
-	calc_mode_timings(xres, yres, refresh, mode);
+
 	return 1;
 }
 

drivers/video/fbdev/core/modedb.c

···
 	  FB_SYNC_HOR_HIGH_ACT, FB_VMODE_NONINTERLACED, FB_MODE_IS_VESA },
 };
 EXPORT_SYMBOL(vesa_modes);
+
+const struct dmt_videomode dmt_modes[DMT_SIZE] = {
+	{ 0x01, 0x0000, 0x000000, &vesa_modes[0] },
+	{ 0x02, 0x3119, 0x000000, &vesa_modes[1] },
+	{ 0x03, 0x0000, 0x000000, &vesa_modes[2] },
+	{ 0x04, 0x3140, 0x000000, &vesa_modes[3] },
+	{ 0x05, 0x314c, 0x000000, &vesa_modes[4] },
+	{ 0x06, 0x314f, 0x000000, &vesa_modes[5] },
+	{ 0x07, 0x3159, 0x000000, &vesa_modes[6] },
+	{ 0x08, 0x0000, 0x000000, &vesa_modes[7] },
+	{ 0x09, 0x4540, 0x000000, &vesa_modes[8] },
+	{ 0x0a, 0x454c, 0x000000, &vesa_modes[9] },
+	{ 0x0b, 0x454f, 0x000000, &vesa_modes[10] },
+	{ 0x0c, 0x4559, 0x000000, &vesa_modes[11] },
+	{ 0x0d, 0x0000, 0x000000, 0 },
+	{ 0x0e, 0x0000, 0x000000, 0 },
+	{ 0x0f, 0x0000, 0x000000, &vesa_modes[12] },
+	{ 0x10, 0x6140, 0x000000, &vesa_modes[13] },
+	{ 0x11, 0x614a, 0x000000, &vesa_modes[14] },
+	{ 0x12, 0x614f, 0x000000, &vesa_modes[15] },
+	{ 0x13, 0x6159, 0x000000, &vesa_modes[16] },
+	{ 0x14, 0x0000, 0x000000, 0 },
+	{ 0x15, 0x714f, 0x000000, &vesa_modes[17] },
+	{ 0x16, 0x0000, 0x7f1c21, 0 },
+	{ 0x17, 0x0000, 0x7f1c28, 0 },
+	{ 0x18, 0x0000, 0x7f1c44, 0 },
+	{ 0x19, 0x0000, 0x7f1c62, 0 },
+	{ 0x1a, 0x0000, 0x000000, 0 },
+	{ 0x1b, 0x0000, 0x8f1821, 0 },
+	{ 0x1c, 0x8100, 0x8f1828, 0 },
+	{ 0x1d, 0x810f, 0x8f1844, 0 },
+	{ 0x1e, 0x8119, 0x8f1862, 0 },
+	{ 0x1f, 0x0000, 0x000000, 0 },
+	{ 0x20, 0x8140, 0x000000, &vesa_modes[18] },
+	{ 0x21, 0x8159, 0x000000, &vesa_modes[19] },
+	{ 0x22, 0x0000, 0x000000, 0 },
+	{ 0x23, 0x8180, 0x000000, &vesa_modes[20] },
+	{ 0x24, 0x818f, 0x000000, &vesa_modes[21] },
+	{ 0x25, 0x8199, 0x000000, &vesa_modes[22] },
+	{ 0x26, 0x0000, 0x000000, 0 },
+	{ 0x27, 0x0000, 0x000000, 0 },
+	{ 0x28, 0x0000, 0x000000, 0 },
+	{ 0x29, 0x0000, 0x0c2021, 0 },
+	{ 0x2a, 0x9040, 0x0c2028, 0 },
+	{ 0x2b, 0x904f, 0x0c2044, 0 },
+	{ 0x2c, 0x9059, 0x0c2062, 0 },
+	{ 0x2d, 0x0000, 0x000000, 0 },
+	{ 0x2e, 0x9500, 0xc11821, 0 },
+	{ 0x2f, 0x9500, 0xc11828, 0 },
+	{ 0x30, 0x950f, 0xc11844, 0 },
+	{ 0x31, 0x9519, 0xc11868, 0 },
+	{ 0x32, 0x0000, 0x000000, 0 },
+	{ 0x33, 0xa940, 0x000000, &vesa_modes[23] },
+	{ 0x34, 0xa945, 0x000000, &vesa_modes[24] },
+	{ 0x35, 0xa94a, 0x000000, &vesa_modes[25] },
+	{ 0x36, 0xa94f, 0x000000, &vesa_modes[26] },
+	{ 0x37, 0xa959, 0x000000, &vesa_modes[27] },
+	{ 0x38, 0x0000, 0x000000, 0 },
+	{ 0x39, 0x0000, 0x0c2821, 0 },
+	{ 0x3a, 0xb300, 0x0c2828, 0 },
+	{ 0x3b, 0xb30f, 0x0c2844, 0 },
+	{ 0x3c, 0xb319, 0x0c2868, 0 },
+	{ 0x3d, 0x0000, 0x000000, 0 },
+	{ 0x3e, 0xc140, 0x000000, &vesa_modes[28] },
+	{ 0x3f, 0xc14f, 0x000000, &vesa_modes[29] },
+	{ 0x40, 0x0000, 0x000000, 0 },
+	{ 0x41, 0xc940, 0x000000, &vesa_modes[30] },
+	{ 0x42, 0xc94f, 0x000000, &vesa_modes[31] },
+	{ 0x43, 0x0000, 0x000000, 0 },
+	{ 0x44, 0x0000, 0x572821, &vesa_modes[34] },
+	{ 0x45, 0xd100, 0x572828, &vesa_modes[35] },
+	{ 0x46, 0xd10f, 0x572844, &vesa_modes[36] },
+	{ 0x47, 0xd119, 0x572862, &vesa_modes[37] },
+	{ 0x48, 0x0000, 0x000000, 0 },
+	{ 0x49, 0xd140, 0x000000, &vesa_modes[32] },
+	{ 0x4a, 0xd14f, 0x000000, &vesa_modes[33] },
+	{ 0x4b, 0x0000, 0x000000, 0 },
+	{ 0x4c, 0x0000, 0x1f3821, &vesa_modes[38] },
+	{ 0x4d, 0x0000, 0x1f3828, &vesa_modes[39] },
+	{ 0x4e, 0x0000, 0x1f3844, &vesa_modes[40] },
+	{ 0x4f, 0x0000, 0x1f3862, &vesa_modes[41] },
+	{ 0x50, 0x0000, 0x000000, &vesa_modes[42] },
+};
+EXPORT_SYMBOL(dmt_modes);
 #endif /* CONFIG_FB_MODE_HELPERS */
 
 /**

include/linux/fb.h

···
 
 /* drivers/video/modedb.c */
 #define VESA_MODEDB_SIZE 43
+#define DMT_SIZE 0x50
+
 extern void fb_var_to_videomode(struct fb_videomode *mode,
 				const struct fb_var_screeninfo *var);
 extern void fb_videomode_to_var(struct fb_var_screeninfo *var,
···
 	u32 flag;
 };
 
+struct dmt_videomode {
+	u32 dmt_id;
+	u32 std_2byte_code;
+	u32 cvt_3byte_code;
+	const struct fb_videomode *mode;
+};
+
 extern const char *fb_mode_option;
 extern const struct fb_videomode vesa_modes[];
 extern const struct fb_videomode cea_modes[64];
+extern const struct dmt_videomode dmt_modes[];
 
 struct fb_modelist {
 	struct list_head list;