fbdev: fix parsing of standard timings

The standard timings parses uses 1:1 dimensions when the ratio in the
EDID data is 0. However, for EDID 1.3 and later the dimensions are 16:10
when the ratio is 0.

Pass the version and revision numbers to get_std_timing() which can then
make the right decision about dimensions.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

1 files changed, 15 insertions, 6 deletions

diff --git a/drivers/video/fbmon.c b/drivers/video/fbmon.c
index 4f57485f8c54..cef65574db6c 100644
--- a/drivers/video/fbmon.c
+++ b/drivers/video/fbmon.c
@@ -493,7 +493,8 @@ static int get_est_timing(unsigned char *block, struct fb_videomode *mode)
         return num;
 }
 
-static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
+static int get_std_timing(unsigned char *block, struct fb_videomode *mode,
+                int ver, int rev)
 {
         int xres, yres = 0, refresh, ratio, i;
 
@@ -504,7 +505,11 @@ static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
         ratio = (block[1] & 0xc0) >> 6;
         switch (ratio) {
         case 0:
-                yres = xres;
+                /* 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;
@@ -533,12 +538,12 @@ static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
 }
 
 static int get_dst_timing(unsigned char *block,
-                          struct fb_videomode *mode)
+                          struct fb_videomode *mode, int ver, int rev)
 {
         int j, num = 0;
 
         for (j = 0; j < 6; j++, block += STD_TIMING_DESCRIPTION_SIZE)
-                num += get_std_timing(block, &mode[num]);
+                num += get_std_timing(block, &mode[num], ver, rev);
 
         return num;
 }
@@ -599,6 +604,10 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize)
         struct fb_videomode *mode, *m;
         unsigned char *block;
         int num = 0, i, first = 1;
+        int ver, rev;
+
+        ver = edid[EDID_STRUCT_VERSION];
+        rev = edid[EDID_STRUCT_REVISION];
 
         mode = kzalloc(50 * sizeof(struct fb_videomode), GFP_KERNEL);
         if (mode == NULL)
@@ -632,12 +641,12 @@ static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize)
         DPRINTK("   Standard Timings\n");
         block = edid + STD_TIMING_DESCRIPTIONS_START;
         for (i = 0; i < STD_TIMING; i++, block += STD_TIMING_DESCRIPTION_SIZE)
-                num += get_std_timing(block, &mode[num]);
+                num += get_std_timing(block, &mode[num], ver, rev);
 
         block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
         for (i = 0; i < 4; i++, block+= DETAILED_TIMING_DESCRIPTION_SIZE) {
                 if (block[0] == 0x00 && block[1] == 0x00 && block[3] == 0xfa)
-                        num += get_dst_timing(block + 5, &mode[num]);
+                        num += get_dst_timing(block + 5, &mode[num], ver, rev);
         }
 
         /* Yikes, EDID data is totally useless */