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edid: Fix string extraction in Monitor Descriptors. 

The ASCII Data String in EDID Monitor Descriptor (3.10.3) is "Stored as ASCII,
code page #437" and may contain special characters like '-'. The isalnum check
should be removed.

Also, the "Monitor Name" (0xfc) does not need to always end with 0Ah, so the
name_descriptor_terminated should be replaced by has_valid_string_termination.

Change-Id: I12a670237e12577fc971c0fbd9b2a61c82040ad3
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/193001
(cherry picked from commit 671f82fd5963e32e72d3886aa242cb3e8519f226)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6996
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
This commit is contained in:
Hung-Te Lin 2014-04-03 19:21:03 +08:00 committed by Isaac Christensen
parent da01d94351
commit 2536c1ac76
1 changed files with 16 additions and 45 deletions
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61
src/lib/edid.c
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@ -47,7 +47,6 @@ static int nonconformant_digital_display = 0;
static int nonconformant_extension = 0;
static int did_detailed_timing = 0;
static int has_name_descriptor = 0;
static int name_descriptor_terminated = 0;
static int has_range_descriptor = 0;
static int has_preferred_timing = 0;
static int has_valid_checksum = 0;
@ -146,18 +145,9 @@ detailed_cvt_descriptor(struct edid *out, unsigned char *x, int first)
return valid;
}
static int isalnum(char x)
{
if (x >= 'a' && x <= 'z')
return 1;
if (x >= 'A' && x <= 'Z')
return 1;
if (x >= '0' && x <= '9')
return 1;
return 0;
}
/* extract a string from a detailed subblock, checking for termination */
/* extract a CP437 string from a detailed subblock, checking for termination (if
* less than len of bytes) with LF and padded with SP.
*/
static char *
extract_string(unsigned char *x, int *valid_termination, int len)
{
@ -167,20 +157,16 @@ extract_string(unsigned char *x, int *valid_termination, int len)
memset(ret, 0, sizeof(ret));
for (i = 0; i < len; i++) {
if (isalnum(x[i])) {
ret[i] = x[i];
} else if (!seen_newline) {
if (x[i] == 0x0a) {
seen_newline = 1;
} else {
*valid_termination = 0;
return ret;
}
} else {
if (seen_newline) {
if (x[i] != 0x20) {
*valid_termination = 0;
return ret;
}
} else if (x[i] == 0x0a) {
seen_newline = 1;
} else {
/* normal characters */
ret[i] = x[i];
}
}
@ -191,7 +177,6 @@ extract_string(unsigned char *x, int *valid_termination, int len)
static int
detailed_block(struct edid *out, unsigned char *x, int in_extension)
{
static unsigned char name[53];
int i;
#if 1
printk(BIOS_SPEW, "Hex of detail: ");
@ -262,21 +247,10 @@ detailed_block(struct edid *out, unsigned char *x, int in_extension)
printk(BIOS_SPEW, "Color point\n");
return 0;
case 0xFC:
/* XXX should check for spaces after the \n */
/* XXX check: terminated with 0x0A, padded with 0x20 */
has_name_descriptor = 1;
if (strchr((char *)name, '\n')) return 0;
/* avoid strncat
strncat((char *)name, (char *)x + 5, 13);
*/
if (strchr((char *)name, '\n') || strchr((char *)x+5, '\n')) {
name_descriptor_terminated = 1;
/* later.
printk(BIOS_SPEW, "Monitor name: %s\n",
extract_string(name, &has_valid_string_termination,
strlen((char *)name)));
*/
}
printk(BIOS_SPEW, "Monitor name: %s\n",
extract_string(x + 5,
&has_valid_string_termination,
13));
return 0;
case 0xFD:
{
@ -1282,7 +1256,6 @@ int decode_edid(unsigned char *edid, int size, struct edid *out)
!has_valid_string_termination ||
!has_valid_descriptor_pad ||
!has_name_descriptor ||
!name_descriptor_terminated ||
!has_preferred_timing ||
!has_range_descriptor)
conformant = 0;
@ -1293,8 +1266,6 @@ int decode_edid(unsigned char *edid, int size, struct edid *out)
nonconformant_digital_display);
if (!has_name_descriptor)
printk(BIOS_ERR, "\tMissing name descriptor\n");
else if (!name_descriptor_terminated)
printk(BIOS_ERR, "\tName descriptor not terminated with a newline\n");
if (!has_preferred_timing)
printk(BIOS_ERR, "\tMissing preferred timing\n");
if (!has_range_descriptor)
@ -1305,15 +1276,15 @@ int decode_edid(unsigned char *edid, int size, struct edid *out)
printk(BIOS_ERR, "\tDetailed block string not properly terminated\n");
} else if (claims_one_point_two) {
if (nonconformant_digital_display ||
(has_name_descriptor && !name_descriptor_terminated))
!has_valid_string_termination)
conformant = 0;
if (!conformant)
printk(BIOS_ERR, "EDID block does NOT conform to EDID 1.2!\n");
if (nonconformant_digital_display)
printk(BIOS_ERR, "\tDigital display field contains garbage: %x\n",
nonconformant_digital_display);
if (has_name_descriptor && !name_descriptor_terminated)
printk(BIOS_ERR, "\tName descriptor not terminated with a newline\n");
if (!has_valid_string_termination)
printk(BIOS_ERR, "\tDetailed block string not properly terminated\n");
} else if (claims_one_point_oh) {
if (seen_non_detailed_descriptor)
conformant = 0;