From: "Antonino A. Daplas" <adaplas@hotpop.com>
1. Created a database of broken displays and their associated fixes.
Original patch from Brian S. Julin <bri@tull.umassp.edu>. Only the
monitor manufacturer and model is checked, perhaps we can also check
for the serial number?
2. Added an all_null check in edid_checksum since the checksum will also be
zero if the entire block is zeroed.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/video/fbmon.c | 82 ++++++++++++++++++++++++++++++++++++------
1 files changed, 72 insertions(+), 10 deletions(-)
diff -puN drivers/video/fbmon.c~fbmon-edd-blacklist drivers/video/fbmon.c
--- 25/drivers/video/fbmon.c~fbmon-edd-blacklist 2004-07-26 21:44:06.458555392 -0700
+++ 25-akpm/drivers/video/fbmon.c 2004-07-26 21:44:06.463554632 -0700
@@ -49,6 +49,21 @@
#define DPRINTK(fmt, args...)
#endif
+#define FBMON_FIX_HEADER 1
+
+struct broken_edid {
+ u8 manufacturer[4];
+ u32 model;
+ u32 fix;
+};
+
+static struct broken_edid brokendb[] = {
+ /* DEC FR-PCXAV-YZ */
+ { .manufacturer = "DEC",
+ .model = 0x073a,
+ .fix = FBMON_FIX_HEADER,
+ },
+};
const unsigned char edid_v1_header[] = { 0x00, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0x00
@@ -65,30 +80,77 @@ static void copy_string(unsigned char *c
while (i-- && (*--s == 0x20)) *s = 0;
}
+static void fix_broken_edid(unsigned char *edid)
+{
+ unsigned char *block = edid + ID_MANUFACTURER_NAME, manufacturer[4];
+ u32 model, i;
+
+ manufacturer[0] = ((block[0] & 0x7c) >> 2) + '@';
+ manufacturer[1] = ((block[0] & 0x03) << 3) +
+ ((block[1] & 0xe0) >> 5) + '@';
+ manufacturer[2] = (block[1] & 0x1f) + '@';
+ manufacturer[3] = 0;
+ model = block[2] + (block[3] << 8);
+
+ for (i = 0; i < ARRAY_SIZE(brokendb); i++) {
+ if (!strncmp(manufacturer, brokendb[i].manufacturer, 4) &&
+ brokendb[i].model == model) {
+ switch (brokendb[i].fix) {
+ case FBMON_FIX_HEADER:
+ printk("fbmon: The EDID header of "
+ "Manufacturer: %s Model: 0x%x is "
+ "known to be broken,\n"
+ "fbmon: trying a header "
+ "reconstruct\n", manufacturer, model);
+ memcpy(edid, edid_v1_header, 8);
+ break;
+ }
+ }
+ }
+}
+
static int edid_checksum(unsigned char *edid)
{
- unsigned char i, csum = 0;
+ unsigned char i, csum = 0, all_null = 0;
- for (i = 0; i < EDID_LENGTH; i++)
+ for (i = 0; i < EDID_LENGTH; i++) {
csum += edid[i];
+ all_null |= edid[i];
+ }
- if (csum == 0x00) {
+ if (csum == 0x00 && all_null) {
/* checksum passed, everything's good */
return 1;
- } else {
+ }
+
+ fix_broken_edid(edid);
+ csum = all_null = 0;
+ for (i = 0; i < EDID_LENGTH; i++) {
+ csum += edid[i];
+ all_null |= edid[i];
+ }
+ if (csum != 0x00 || !all_null) {
printk("EDID checksum failed, aborting\n");
return 0;
}
+ return 1;
}
static int edid_check_header(unsigned char *edid)
{
- if ((edid[0] != 0x00) || (edid[1] != 0xff) || (edid[2] != 0xff) ||
- (edid[3] != 0xff) || (edid[4] != 0xff) || (edid[5] != 0xff) ||
- (edid[6] != 0xff)) {
- printk
- ("EDID header doesn't match EDID v1 header, aborting\n");
- return 0;
+ int i, fix = 0;
+
+ for (i = 0; i < 8; i++) {
+ if (edid[i] != edid_v1_header[i])
+ fix = 1;
+ }
+ if (!fix)
+ return 1;
+
+ fix_broken_edid(edid);
+ for (i = 0; i < 8; i++) {
+ if (edid[i] != edid_v1_header[i])
+ return 0;
}
return 1;
}
_